Let's look at what would be the most simple explanations for the behavior of President* Trump. These are not accusations or allegations, they're merely assertions for the sake of argument.
What if the reason he is not releasing his tax returns is that he has huge loans which can be traced back to laundered money from Russian oligarchs and/or the Mafia?
What if the reason he does not divest from his business is that he is in the red, i.e. his debt is larger than the total value of his assets, and he is effectively bankrupt?
What if the enormous amounts of smoke surrounding the issues of Russia and Putin are because there is fire behind it?
What if he is actually stupid enough, and deluded enough, to think that he could get away with all this?
Wouldn't everything suddenly make a whole lot more sense? It would mean that there is a huge criminal case to be brought against an illegitimate president and a number of his associates, but the alternative is to believe in an increasingly implausible and ever expanding set of remarkable coincidences, and putting faith in the innocence of people who are looking more guilty with each passing day.