I don't think the "definition" of masculinity can possibly be changed, as it's a very personal concept.
I consider myself masculine in that I have the right chromosomes and the right body configuration. I grow facial hair, my hair is thinning out on top of my head, and I tend to gain and lose weight around the abdomen. Like most guys. Ergo, I'm a guy.
Beyond that, who gives a shit? I used to watch "Sky Dancers" as a kid because its male-centric equivalent was boring as fuck. I watch MLP for the references and occasionally for this or that clever plot twist I've heard about. I don't hide my interest, but neither do I plaster it on every wall I cross.
If you want to go into "traditional" points of view, then what? Do I need to be as buff as Mayor Mike Haggar to pass muster? Do I need Chuck Norris' purported godly abilities to pass? Should I fire up "Predator" and use a freeze-frame of 80's Jesse Ventura to get some sort of frame of reference? Or maybe this "masculinity" thing is referring to how my grandfather handled things, in his prime, huh? Maybe I'm supposed to be sullen and absent and generally numb to the concerns my loved ones might verbalize because "Big Boys Don't Cry"...
In short, the very concept of masculinity feels silly - just as femininity does. The girliest of all girls I've ever met still was able to stereotypically "man up" to have fun with my dude-friends. An important fact to consider is how until late in the nineteenth century, it was actually considered manly for men to wear pink. The whole robin's-egg-blue = boys thing wouldn't surface until much later.
Go back a few centuries earlier, and you run into the haberdashery customs of the Enlightenment. What was the manliest shit, back then? A powdered wig, buckled shoes, high stockings, tons of rice powder for base makeup, some lipstick and a bit of black felt on the cheek, to simulate an artfully placed beauty mark.
As to why? People didn't really wash, back then. You caked yourself in makeup to hide the layers of filth you lived in, regardless of your status as a member of the aristocracy.
So, yeah. Anyone who tells me that this or that or so-and-so is "gay" or "effeminate" usually smacks of sheer idiocy or hypocrisy. The Idea Channel raises good points, but manhood is a concept that ultimately exists in the eye of the beholder.