Acting doesn't mean that a person has the look or persona to play a role. Which is where most people, self included, seem to stand on Affleck. He doesn't seem to "fit" as a Batman.
How about just speaking for yourself and not presuming what other people think.
And I'm not sure what you mean he doesn't "fit" as Batman. Actually I do know what you mean, you mean he doesn't fit your idea of Batman, which is fine. But don't pretend to presume it's what everyone thinks.