Fursuits are fine when they're done right, but they rarely are. I don't see the appeal of the extremely cartoony ones.
I also don't believe that they should be worn out of context. There's a place and time for it, but if you wear one everyday you can't complain if you get berated for it. I'm sorry, but if you don't like getting made fun of then you should probably save it for a fur-con instead of wearing it to the grocery store. Self-expression is nice and all, but to do someone as extreme as wearing a fursuit in a public populated area where everyone else is just trying to go about their business is kind of rude, in a way. It's almost like begging for attention and that sort of thing bothers people. I personally find it hard to feel sorry for people who complain about getting made fun of when they're wearing the whole tail, ears and harness combo to school. If you can't stand the bad attention then you probably shouldn't make yourself troll-bait.
But sure, at a fur-con or a fur party or whatever is fine. I personally like the more realistic looking ones, and I wouldn't mind owning a nice pair of horns myself, claws would be nice too. I would want a Xenomorph tail, but that would be too bulky and what's the fun of it if it doesn't move and can't stab people through the stomach?
While I agree with you that some folks do not choose the right place nor time for wearing their fursuits, partially because of the wrong motives, that is the only part of your post that I will agree with. Cartoony fursuits have their place in the fandom as well. It's all a matter of personal preference as to which sorts of expressions you want to make.. and yes, I DO wear my fursuits to places other than fur-cons and parades. I absolutely LOVE wearing my fursuits out to places like the local park or, with prior arrangements with the venues, places like the mall with a couple other suiters and a spotter. I don't know who gets more excited sometimes, myself, or the children! I love being able to bring that little spark of "disney world" to kids on otherwise ordinary days. I can't articulate the awesomeness that a little simple fursuiting can do, so I'll point to a reference.
The Magic of FursuitingI'll admit I compare myself fursuiting to Disney World because fursuiting DOES have something in common with DW.. it brings out the kid in all of us