You'd get a howl of argument from me on that one, if only because it's not your right as DM to tell me how to play my character.
If my character doesn't fit in with the party it's up to the party - in character! - to deal with, either by accommodating him or throwing her out or leaving him behind or killing her outright. Or just making things such that my character's best option is to leave.
Kinda. I've had times, over the years, when a play brought in a character that just never clicked with the group. Most of the time, the player realizes this and either tweaks the character or switches again. A few times, though, they insisted on continuing to bring that character to the table every week. It could be that the party is Good aligned and the offending character is being the annoying tag-along so they wouldn't necessarily take drastic action strictly in-character, but the
players want the character gone. Or, I've also had a player tell the rest of the table, in a raised voice, that they all just need to stop raining on their parade and everyone at the table can have fun in their own way.
In either case, if all else fails, it's the GM's responsibility to step up and actually referee (which is a term interchangeable with GM/DM). I have a lot more sympathy for the first player, though, than the second. For a concrete instance, we were playing a mixed nWoD game and one of the players was trying to do an EMT (I think), but the way things worked out, he came off as a creepy guy with a white van and some candy -- which is really weird because the player is super likable, personally. After a few sessions, we decided that, since he'd switch to a Changeling and the character he'd been playing was actually his fetch, which is why everyone got vibes from it. Problem solved.
In the second case, I have a lot less (read: zero) sympathy. When there are a half-dozen people at the table, there needs to be a willingness for everyone to work together. Maybe you really wanted to play an Outer Rim Star Wars game, but everyone else really wanted to play Dark Sun. You do not get to throw a fit about the GM being the guy to tell you that anything that looks like a blaster is inappropriate. There may be an option that isn't anyone's first choice, but everyone thinks would be fun. If you yell and throw a fit, I will call you out.
Also, the GM gets a bit of veto power, just because they have to keep the plates spinning. The game needs to be fun for everyone and the GM should take feedback. The GM does not have to run a game he doesn't enjoy, though. For my part, after 35-ish years of gaming, mostly GMing, I've learned a few things that will make me hate running a game and I call them out, up front. There's a lot on my list I'm fine playing along side, if someone else wants to GM, but I'm not going to run a game where I think I'm not able to help you move your character along.