"Reaction" is the key word here. The opposite of a fanboy is not a hater, it is the person who doesn't care. The fanboy and the hater are two sides of the same coin - they both develop an obsession with a person and define their personalities as a function of this person. Whether that function is love or hate is secondary.
The way out of his is to ignore him, or judge him by his work. He sells cars - really good cars. For example, they have the best range and are incredibly safe. Your emotional reaction won't make you car's range go down, or make you any less safe in a crash.
And any thread that involves him; I'm not good at this, but I'm trying. The reason Elon Musk inspires such hate is because he is constantly PRing (generously) unverifiable claims, but rarely gets any consequences from it. If he would let his work speak for itself, there would be less haters; his companies are clearly doing some things well.
It's kind of a Steve Jobs thing, but Jobs rarely made forward looking claims -- sure his claims of invention were irritating to some, but they were about a product that existed at the time of the claim.
His behavior of overpromising and underdelivering is a deliberate strategy to drive productivity within his employee base. You may not like that approach, but it seems to have worked.
You may judge him to be "terrible at executing" if you compare his output with his promised output. If you compare his absolute output with that of a common industrious person, you'll find he scores off the charts.
Elon Musk is great at promising stuff, and then terrible at executing. For every promise he fulfills there are 20 that he doesn't. But sure, the guy who flies private everywhere and shitposts more than I do is "working 100 hour weeks" and "cares for the environment."