How, exactly, is it slander? Trump himself said he'd never asked for forgiveness...and frankly, that's the way narcissists are. What's more, Trump is malicious, thrice-married, is a serial womanizer, and does not have a happy marriage...whereas Obama is happily married to the same woman for 25 years. Trump despises the poor...and one need only look back at how incensed the Pharisees were when Jesus went to go preach among the poor, among those who were not "worthy" in the sight of the Pharisees.
Obama sincerely tries to comport himself as a Christian in word and deed...whereas Trump couldn't care less about how Christians are supposed to act. And let's not forget the fact that Trump's told literally hundreds of lies since he took his oath of office...sometimes contradicting his own words in less than 24 hours. Trump shows real compassion for no one, and has continually whined about how unfair the press is to him when all they're doing is simply pointing out the things he has done.
Look at Puerto Rico - those are American citizens there, and the island is STILL about 50% without power even now! Can you imagine any of our past presidents simply leaving over two million American citizens to simply wither on the vine like Trump is doing to them? Oh, wait, I forgot! Since PR doesn't have any electoral votes, why should Trump care? But none of our past presidents would be so callous, so dismissive of the lives and livelihoods of two million American citizens.
Only Trump would.
Indeed, by their actions shall ye know them...but first, you need to acknowledge those actions, and you can't do that if you only listen to the right-wing media that never points out those actions.