Let me start by saying I don't really know anything about this issue, I'm just reacting to what the primitive is alleging to have happened.
Its kinda difficult for the libs to make this case against Trump - as far as I can see, he hasn't been elected to anything yet. - That's the difference. The Clinton's seem to use promises of political access to those who contribute. Trump didn't because he can't. Not to mention, this is Trump making the contribution, not the one receiving it.
So, if there is 'corruption' - it would be with the one he contributed to. - That's assuming the primitive isn't distorting anything, which is unlikely at best.