That may or may not be the case with Trump. Accusations against trump of sexual predation are still unproven.
Yes it's proven he had an affair, but that isn't predatory behavior. Try he affair itself may not even be "immoral" if he and his wife have an open relationship (that's between them).
I consider Bill Clinton's relationship with Monica to be predatory, because she was an intern, and thus a subordinate. There was a formal power structure in place that calls into question the validity of her "consent".
While both Bill Clinton and Trump have had unproven accusations of sexual harassment (and in some cases rape), many if the accusations against Clinton have more substantiation than those against Trump. (Some of the accusations against Trump have been proven to be impossible, as he can prove he was elsewhere at the times and places of alleged incidents).
But honestly, this meme was primarily a response to multiple misogynist insults I've seen directed at Melania on various social media.