If you voted for Trump, I don’t think you can consider yourself libertarian.

I wouldn't go so far as to draw that line at voting, as one could certainly be voting strategically -- it's possible that they don't agree with many, if any, of Trump's policies, but they were of the belief that voting for Trump would push policy in a direction that would be in their interest -- this is, of course, a symptom of FPTP, and it could be possibly solved with a ranked ballot. That being said, I do completely agree that if one is a vehement supporter of Trump, and his policies in a similar fassion to the usual MAGA group, then they cannot call themselves a libertarian in good concience -- there are many policies of, and actions by Trump that are very un-libertarian.