Alzrius
The EN World kitten
But it is limitation on what kind of character you can have. That's the functional issue, and not something we should forget.
Speaking purely to the broader issue of players having limitations on what kind of character they can have, this isn't something that's universally condemnatory (or at least I don't believe it is). In terms of world-building, what isn't allowed can be just as important as what is, and it's entirely possible to have characters that - whether by game mechanics or role-playing - are disruptive because they go beyond the boundaries set by the GM or the source material.
For example, our GM once announced that his next campaign was going to have a Gothic Horror theme. We were all happy with this, but two of the players had already decided that they really wanted to play tag-team luchador wrestlers, one of which spoke in faux-Spanish, and the other talked like Hulk Hogan. The GM didn't ban their characters, instead trying to work around them, but it caused the tone of the campaign to take a big hit.
This is without getting into the issue that ability scores are the aspect of character generation where players have the least agency, being restricted to random rolls or a limited allocation of points.