A player has the right to make the character they want, however they also have an obligation to the other players to not hinder the rest of the group with their character choice.*
* Don't think this only applies to suboptimal characters. This also applies to the selfish jerk who wants to play an Assassin in a predominantly Lawful Good party, or a Paladin in an evil group, or any other strange character that doesn't fit in with everyone else.
I'd ignore everything after that first comma, personally.
If someone wants to play an assassin in a predominantly LG party, eventually, he'll "see the light" when infraparty conflict arises, or they don't bail him out, or what have you.
As for the Paladin...that could be a VERY short lived party once he uses Detect Evil...
Or, to put it a different way, my choice to play a halfling barbarian with 2wf in no way affects your fun- if it does, that's YOUR problem, not mine.
Honestly, the last time a player griped about my PC design (and he DID just go on and on), I ripped it up in his face and asked him if he was happy. I didn't leave the group (at the time, I was the sole host). He hasn't bugged me about the way I design PCs since then, and I haven't changed my style.
Fast forward 5 years to the present day- that player is now the DM running us through RttToEE (in 3.0). My "suboptimal" Ftr/Rgr/Diviner/Spellsword is optimized for 2WF (not that he's supposed to be in combat, of course)...but is currently being forced to carry one of the 2 magic 2 handed swords we've found, since every better warrior in the party has a valid reason for not carrying it- a druidic weapon restriction; already carrying one of the swords; a vow...
So now I've got a PC who is essentially everyone's understudy being forced to the fore...and I'm taking grief for it. They conveniently ignore or forget the good stuff I've done...like rescuing the drowing "legitimate businessman" because my PC was the only one with "Swim" ranks...or finding the PC who got T-Ported away by the enemy.
But NOBODY criticises my PC design choices in anything other than a good-natured jibe. Sometimes all it takes is a single vivid and easily remembered lesson to illustrate how rude one person is being for everyone to get the message.