No, while I suspect that many of the people who voted for Trump did so out of bigotry, some I assume are good people.

And the email did not say to resign if you supported Trump, it said to resign if you would engage in bigoted acts. "demeaning, insulting and ridiculing minorities, immigrants and the physically/mentally disabled" is how those acts were specified. And frankly, if that's how you're going to behave, then you have no place in any organization.