You're right, of course: Hillary Clinton, not Bill, was the Democratic nominee for president in 2016. Beyond that, however, is the fact that the differences between Bill Clinton and Donald Trump. like the differences between Hillary and Trump, are not differences only of degree but of kind. 
Trump is in his third marriage, subsequent to multiple, well-publicized adulterous relationships.  He’s been accused of domestic and sexual violence, up to and including accusations of marital rape (by his first wife) and child molestation (in a civil suit).  He boasted that avoiding venereal disease was his “personal Vietnam.” He’s lived a filthy life, and boasted about it. Compared to Trump, Bill Clinton is a paragon of marital fidelity and sexual restraint.  While Clinton’s misconduct is indefensible, he had at least enough decency not to brag about it. The Clintons managed to save their marriage. By contrast, Trump has always regarded his sexual promiscuity as a point of pride. Deplorable.