Well, at least we won't have too argue about it, because I agree , it's a shame when people start hating on each other...
I for one do not care much for the earlier generations, I'll be honest about that. Yes I may have seen the occasional episode when I was younger, and I even know that there was a human girl in the series once that was named Megan I think? No clue which generation that was from tho... But I became a fan of MLP (but obviously just this new generation) at the time I discovered the new show, which would be since the second episode aired. And I'm sticking to it. The older generations are just another show for me, and it's just not to my liking.
But altho I do not like the older gens, I personally won't condemn anyone for it, because really, what's the point in doing that? That's for everybody to decide for themselves. It's just as pointless as the hate on bronies in general. Besides, there are many reasons to like stuff (be it MLP or not), be it the humour, storyline, setting or even underlying things like nostalgia. People bashing/raging on others for things like that are very often just attention seekers, have no arguments to speak of and when countered with either politeness and/or seriousness (while staying civil of course), they'll react either like butthurt crybabies, run for cover, or just admit defeat. That is at least my experience.
If they rage on you for being a fan of the earlier gens, just remind them of the fact that that is the show that has spawned this new gen AND that you are entitled to your own opinion, just as they are. But it's like they say, 'haters gonna hate', it's up to you to handle it . But that doesn't change the fact that all the hating/bashing/raging is, seriously a shame .