One factor is that even if you think Musk was just mucking about or misunderstood, there is still the embarrassment of other people thinking your car choice endorses that.
The post had a number of grammatical errors too, so if "whilst" we're at it, should we criticize all of European education? Please don't post low-effort negative nationalism. It's cheap and the subject (the richest person alive is apparently a nazi) is a serious matter.
... You think the majority of people don't care about Nazi salutes? I mean, certainly if we're talking Europe, yeah, sorry, the majority of people do care about Nazi salutes.
I think, also, that the kind of sneering, what would you call it, implausible deniability maybe, thing the US far-right like to do where they do something outrageously and then smugly deny that they did it, works less well in Europe (I'm not sure why Americans are so tolerant of it, tbh).
I think the only people who care about this are people who care about politics in the first place or didn't already like Elon, which isn't everyone and probably not the majority.
Whilst Elon has some blame for Tesla's bad brand image, competition in Europe has made it so if you go Tesla your basically paying a premium for the brand and that's it, Tesla's in Europe iirc have self driving capability much less than the US.