That's not always the case, though. Biden didn't get away with his "You ain't black" comments, and in fact, faced all sorts of blacklash over it (and yes, a lot of it was Trumpsters pointing fingers and saying, "SEE! THE DEMS ARE THE RACIST ONES, NOT US!!"), and it honestly was a really stupid thing to say. Sure, he recovered from it, but it was a shot in the foot, let's make no mistake.
And let's not forget Al Franken: Dems immediately ousted him after sexual harassment allegations came out against him involving him being inappropriate with a teen girl - something any Rep would get a free pass for, because, "That was in the past, and God has forgiven them, and besides, this is really only between them and God anyway, it's none of our business."