As a hunter owner, I'd say it's two things:
1) Everybody likes to criticize, as it makes us sound more intelligent. Nobody gets on TV by being nice, after all...
2) When you own a hunter, you notice more of the dissuading comments regarding hunters. If you own a mini-van, you notice the disparaging comments about mini-vans. If you own a gun, you notice the gun comments. If you own a ... anyway, that's my bet.
There's no more 'hunter hate' than there is 'catalina hate' or 'mac hate' or 'burger king' hate. But if you own a hunter and don't eat at burger king.. well.. guess which part sticks out in your memory when you think back ...
In other news.. a lot of those hunter-haters raise good points. No boat is perfect. There's a gem of wisdom in most steaming piles of verbal diarrhea.
But I still bought - and am quite happy with - my hunter. Sure, it's a pig, tender as all get out, and can't carry a jib much larger than a handkerchief, but it's a great little daysailor with a ton of room and simple enough to sail that 8-year-olds can walk away from an afternoon of fun and feel like they learned something enjoyable. It's not an offshore cutter with 18 control lines for each sail, but it does what I need it to.
So I'm not terribly concerned with the critiques of things I know to be true, but consider necessary evils in order to have the things I want.
Least I don't own one of those cheap-arse mac's, huh?