I think what Jim is missing is that there are differant styles of humor. What's funny about Duke is that it's taken seriously within the context of his game world. We as the people get to snicker at how preposterous it all is. It's a differant style than having characters within the game world take him down a peg, rather it's funny because they don't, and I think all the humor out there with the over the top he-man getting taken down, or one-upped constantly by the female co-role, or whatever is exactly what helps to make this funny.
It's not just in the Jimquisition, but in the media in general, that I've noticed this tendency to claim that Duke Nukem is being presented as some kind of icon. Truthfully, I have never gotten that impression, he's presented as being pretty bloody absurd.
I will also be honest in saying that the whole "too cool for school" thing isn't something that was the product of a bygone decade, after all that whole attitude was just as absurd then as it is now. Today people point back to the 00s and 90s, in the 90s people pointed back to the 80s, and in the 80s they pointed back to the 70s... and well mass media culture of the type we're dealing with doesn't go back much futher than that in the context we're talking about, at least in examples I could clearly point to. What we're dealing with is something that is "corny", and to be honest the things that are truely corny were never taken seriously in any decade. Certain properties however manage to make something corny, really cool at the same time (and you can replace corny with campy on other subjects where the reality is simple), of course that kind of corny-cool tends to lose something when it's beaten into the ground too much... which is what happened with Sonic The Hedgehog. Duke Nukem goes for a differant style than Sonic, but it's the same basic argurment, but with Duke it's been so long between actualy games that he hasn't worn out his welcome.
If you want to look at an example of what Duke Nukem is going for, think of the old "Buckaroo Banzai" movie, which managed to become a cult success. Buckaroo Banzai was basically the same schtick as Duke Nukem, albiet without the explicit sexuality (although by definition all the women in that universe were madly in love with our hero). Buckaroo Banzai basically could do anything, and was an expert in every field of human endeavor, he had friends and allies to the four corners of the earth, he had his own worldwide secret society to boot. His enemies were equally absurd world threatening aliens. Fans of that cult classic had been clamouring to actually make the promised sequel, but at the same time if they had actually delivered on turning that into a franchise, it would have gone the way of Sonic.
With Dante, they were actually trying to go for a comic-book type thing from what little I've read on the subject. Dante's antics were inspired by those comic book fights where you occasionally see a hero or villain so in control of a fight against someone that they outclass that they do something absurd with their powers to make that point and humiliate their opponent. Sometimes this is combined with an artist showing off what kind of cool things an artist can do with sequential art as a medium, sometimes simplistically. I could give an exhaustive list, but I'm sure any comic reader has occasionaly gone "he just did what?" from that kind of situation. The thing is that Dante overdid it. If some bad guy attacks, and gets KOed by The Flash, but then you find that in between the bad guy launching his first blow, and him being put down The Flash also took the time to do all the housework, cook a four course meal, and check his sidekick's homework on the other side of the planet, that's funny as an occasional thing, and as a humorous reminder of how fast he actually is (capable of bending time to literally be in multiple places at once) but if he does it every single fight it goes from being cool, to just being stupid.
To be honest I think people are decrying the macho-nature of Duke, and inentionally claiming to not "get" the style of humor (and yes, it is humor, not intended to be taken seriously) due to the pressure the games industry is getting. It's kind of frightening when I see guys like Yahtzee going on about the media going too far with violence, and guys like Jim with the same basic platform (as to the amount of views they can get) going off about Duke. To me it seems like an attempt to compromise. Games are getting mainstream attention, and thus need to start conforming with what the mainstream deems acceptable for content. The kind of humor at the root of duke, or the extreme over the top gore of Mortal Combat, are basically no-nos in the sphere of political correctness. The humor coming from Macho men has to come from watching them be cut down to size, as opposed to watching them get away with it and have everything go their way and simply chuckling at the absurdity of it... basically it being funny because it's so wrong, and the guy isn't getting cut down to size like we'd expect from like 99.9% of the rest of the humor media out there.
Right now is the point where video games need to have their extreme content, and irreverant concepts defended. Video games need to be put into society as they are, not made to adapt to the same norms they have spent decades fighting against. If this battle is won, it can also be a major springboard for other forms of media to break free from the contraints we're seeing.
When I listen to Jim here, I basically get the impression that what he wants to see is another generic sitcom, you know where the man comes home starts to act stereotypically manly, and gets cut right back down to meterosexual size by his spouse or girlfriend. That is a TYPE of humor, and the most politically correct take on gender roles, but it's not the ONLY type of humor. Granted the kind of Absurdity inherant in Duke Nukem is akin to the jokes in a Men's Locker room... but hey, it's never been making any pretensions about that. Old school Andrew "Dice" Clay with a gun and an alien invasion is a valid approach, even if some want to belittle it.
Personally I defend Duke because I like variety and right now there isn't anything quite like him out there. I'm not a big shooter fan, and probably won't be getting his game until it's on a STEAM sale or something. Make whatever judgements you want about me for defending this kind of thing, but I think it's something that should be embraced, rather than basically going after it specifically for NOT being politically correct and going along with all of the other stuff out there. "The Dice Man" was never one of my favorite Comedians, but for all the criticism, I think the comedy landscape was better for his prescence when he was at his politically incorrect worst. I also don't think you can judge people who find the politically incorrect funny, as long as they understand fantasy from reality and try and take it seriously out into the street.