The point is that he should have done what every President and pretty much potential President has done for ages.
Clinton did it with all of her apparent dodgy crap.
Makes him look shady.
A leaked (probably by him) front page from twelve years ago doesn't do anything to change that.
It's not left or right.
And it's not actually about how much tax he paid.
It's about his character.
Apparently his testosterone is through the roof though, so we can all relax on that score.