Not the only factor, to be sure, but the off-putting icing on an otherwise average cake. If Tesla were the only decent EV in town, I might hold my nose through Musk’s behaviour and buy one. They aren’t, though, so I don’t have to.
The other major factors in my decision are the very public QA issues, safety issues, and questionable design decisions (eg. all-touchscreen controls, dangerous “full self-driving” fallacy) that, combined, leave me thinking “yeah, maybe I’d rather buy from a somewhat more boring company with a longer history of _making safely-working cars_”
I don’t kid myself that the heads of most car companies are necessarily decent human beings who align with me ethically or politically, but all other things being increasingly equal, why would I opt for the one run by a childish unstable egomaniac who stands in loud, public opposition to most of what I believe in?