Short answer: yes, fun game = good games by definition.
But the truth is that games are judged in three sectors, each of which people misjudge "goodness" a game on.
There are three standards to grade a game on. 1) production quality 2) morals/offensiveness 3)fun.
1) Production quality is easy to agree on. Everyone thinks Metroid: Other M has solid graphics, good controls and is bug free. Everyone agrees that Battlefield 3 is great to look at. And everyone thinks that Deus Ex 1 looks like shit today.
2) This refers to does it teach morals/ is it offensive/ is it true to the franchise. Some games are not fun and have low production quality but have great morals. Many think that Deus Ex has solid philosophical questions, that Halo might have a solid precautionary tale against zealousness, and that Mario has no morals or anything (most games are like this). Some games are offensive, like Ethnic Cleansing. And lastly there is being true to the franchise. Nobody thinks that Halo has ever strayed far from its canon and saw the RTS Halo Wars as acceptable and a fun change of pace. People were able to adapt to a new setting from Half Life to Half Life 2 easily and many consider Metroid: Other M to be a war crime and X-com the FPS to be a betrayal. This is regardless of if the game is fun or has high production values. There is generally not much debate in this section.
3) Fun factor. This is where personal taste and opinion enter a lot. Did "Streets of Fury" (available for 3$ on Xbox arcade) have a moral lesson, no. Was it a technical masterpiece, hell no. But was is really really fun, HELL YEA. A game that is fun will be played even if it is low in production quality (why people prefer Deus Ex 1 to Deus Ex 2) or has no morals (Mario) or is untrue to the franchise (some liked Metroid Other M. Many liked Fallout 3 even though it betrayed Fallout 1 and 2).
The best example is Perfect Dark for Xbox 360. The game has great graphics, few bugs, great weapon selection, multiplayer and splitscreen co-op. It has generic morals about evil corporations and was true to the franchise. But it was boring and no fun to play and as such was deemed "not a good game".
If you want morals, watch the History Channel and read books on history and morality. If you want high production values, go make a computer or something. The reason you game is to have fun, and as long as the game does that it is good.