Whenever I hear someone say that Nintendo sucks because all their games are to childish and are retarded of it, it makes me want to punch them in the face. Like X-box fanboys that say Nintendo sucks because it doesn't have any games like Halo on it. All I have to say to them is that if their was no Nintendo, Their probably would be no such thing as video games right now, and it leaves them with nothing else to say.
I can't say that that's the best way to go around it. Just because Ford came first, everyone must like Fords*? Instead of wishing to punch one in the face, try instead, "Yes, and that's all good, but Nintendo makes some superb third-person platformers, unique games that make use of the Wii's motion control and The DS's touch screen, and there's always Super Smash Bros. It's a matter of taste."
Or just ignore them. You know they don't actually play the games they call kids' games and just make a generalization about all of Nintendo because Mario stands out most. In such a case, you could end it with "'E' means 'Everyone.' Not 'Kids.' 'Kids' starts with a 'K.'"
And of course, the final and best way is to play
everything. A bit of a financial challenge, but aren't you above everyone who participates in console wars when you know the good and bad of both sides?
*I drive a Ford, but I was just making an analogy.