Everything you say is true. Hillary was a gift to Trump. She is so reflexively loathed by many. She only has herself to blame for some of it e.g lying that you were under sniper fire when you actually calmly walked across the tarmac. But the hate isn't proportional to her sins. Biden would have won. The death of his son altered several trajectories. Candidates do have flaws but it's hard for anyone that can consider two disparate thoughts simultaneously to say that Trump was the lesser flawed candidate, even if he was saying things politicians don't usually say. (We'll put aside the part where he was saying things just to win).
So what we have here, at the risk of being called "elitist" are a lot of dumb people in the US, Republicans and Democrats. (People that voted for Obama not for qualifications but because he was black = dumb). Yesterday, Washington Post ran an article about Trump voters in the Midwest. One guy said the Russia investigation was Democrats playing sour grapes because they lost in 2016. This despite the fact that the Special Counsel investigation was started because a Republican (Rosenstein) appointed a life-long Republican (Mueller) because the life-long Republican head of the FBI was fired, to mention nothing of the fact that the Senate & House also had Russia investigations.
Yes, the hatred of Hillary isn't proportional to her sins. The problem she is not a natural politician. She always seemed uncomfortable and it always seemed like she thought it should be a coronation. Apparently, so did the DNC and the liberal media. Much has been written and criticized about our long campaign cycle, but it has been said that it rewards candidates who organize, manage, market and adapt under extreme pressure. I don't think Trump was a great organizer, but he knew how to market and adapt to the audience. It was kind of a guerilla campaign that Republican primary candidates didn't see coming and adapted to anemically. Hillary was also a terrible manager. She should never be forgiven for essentially ignoring the Rust Belt. (Perhaps the Rust Belt voters are the stupid people in the U.S. that you are referencing.) Bill Clinton warned her handlers that this was a mistake.
Your comment on the Mueller probe is vexing. It has become a very divisive issue. If Mueller comes up with something substantial related to Russian collusion, most of the country will unite behind the consequences for Trump. You will find most of the news chatter here about Mueller pursuing obstruction, Stormy Daniels and unrelated business dealings is very divisive. Even if Mueller and Rosenstein are Republicans, Trump is loathed by many inside the beltway Republicans.
Perhaps I should've said elections are always about two candidates with flaws and......flaws are measured subjectively. You can't simply tally flaws and score the candidates. You can't say that people are stupid if they voted for the candidate with 9 flaws versus the candidate with 5 flaws.