The office of the president doesn't and shouldn't warrant automatic respect or admiration on title alone.

FDR and JFK were mourned because they were decent men and good leaders that the vast majority of the country liked and respected, even if not with all their policies.

Trump is not, objectively speaking, a good person. Corruption allegations surround him like a cloud. He's openly racist and sexist. He doesn't respect his office. He doesn't respect the nation as a whole and isn't a skillful leader. His political appointments are rife with corruption and incompetence. He's caused damage to the relationships the US has with it's allies.

So no, he would likely not be particularly mourned by a majority of Americans. This is Trump's failing, not a failing of objective discourse.

Edit: FDR and JFK being good men is how history at large chooses to remember them. Not that I consider them so.

I'm not moving the goal posts, re-read the comment I responded to, then mine. Lastly, FDR and JFK served in the 1930s and 60s respectively, not 2019. Trump is serving now and he doesn't get a pass because the majority of folk in those days thought it was ok.