Not Everybody Thinks This Way, So You Can Take Others' Votes as Given
A common objection to this is that if everyone thought this way, the Wrong Guy might win. The fact of the matter, though, is that not everyone thinks this way. You can safely take others' voting behavior as given and understand that your individual vote will not be decisive at the margin. This should free you to vote however and for whomever you choose.

"You can safely take others' voting behavior as given and understand that your individual vote will not be decisive at the margin. This should free you to vote however and for whomever you choose."
Or not at all.