Major League Baseball and its fans weren't "ready" for black players when Jackie Robinson was hired. The Deep South wasn't "ready" for integration when Rosa Parks and Martin Luther King and the Civil Rights Act came into play.
The status quo is never "ready" to change. That's why it's the status quo.
Of course, the status quo is often less solid and changeable than it appears. Jackie Robinson still faced racial challenges after he was hired, but the public and the players turned out to be not nearly as racist and dead-set against him as the pundits of the era predicted, either when it happened or when Robinson was able to perform and demonstrate that he wasn't some demon that had to be resisted at all costs.
Also: waiting until one is "ready" implies one has a right to do so:
'The NFL has no moral right to be "ready" for a gay player, which is to say it has no right to discriminate against gay men at its leisure which anyone is bound to respect.'
Good article.
The NFL Will Never Be ‘Ready’ for an Openly Gay Player
It doesn’t matter whether the NFL wants to accept an openly gay player like Missouri defensive end Michael Sam. He’s arrived, and the league will have to adjust accordingly.