Musk has been using his money to influence politics (including in the US, accross the board). Buying a Tesla is giving him money and thus supporting that behavior. It seems obvious to me (a European living in the US) that, if you disagree with his politics, you should not buy his cars. This also apply to people living in the US but, having seen a strongly pro choice north Californian friend buy a Tesla recently, I do not know if US citizens think in those terms.