On your first point, I don't think most (fiscal, small-gov't) conservatives would have much problem with tax incentive for electric vehicles, or anything that generally reduces taxpayer burden. But they are typically vocally against subsidies and grants that favor particular individuals or companies over others -- which is not only unfair, but also adds to more spending. It does little, but to help justify a bigger gov't.
Secondly, SpaceX have been spending millions in political lobbying and McCain's political campaign is among many who benefited from such largess (and his own McCain institute) from Musk. Most Americans don't see this kind of lobbying activities with millions dollars spent on politicians as a "fundamental building block" of a well-functioning gov't, but a corrosive force that serves interests of a few at the expense of the majority, however well-meaning in the eyes of Musk supporters. I personally don't see any problem with organizing an interest group to better represent their views -- or lobbyists -- but when it involves so much money and the final outcome ends in lopsided legislation favoring one particular individual or company over others, it's probably a good time to question their "invest-in-politicians-who-can-help-you" relationship.
Ideologically, McCain's views are aligned with those of the "neoconservative" wing of the republican party -- he's mostly known for aggressive foreign policies, American democracy everywhere, and subsequently pro-Military Industry Complex (MIC) which inevitably all leads to a bigger gov't. While most conservatives are also for strong national defense, not everyone is necessarily on board with permanent warfare and welfare (and police) state and that's why "other" conservatives are so annoyed with McCain.
So, once you put these together, it's not too difficult to see why the holy alliance between Must and McCain is criticized by those on the right. They are not necessarily grounded on "anti-facts" or alt-right views as you mischaracterized here. It's just too bad that your pathetic, uninformed comment had to start with the poisoning the well logical fallacy.