Calling someone a bigot used to be a serious accusation. However, the overuse of this term has rendered it almost meaningless.
In this post, Ester said that people who think that males should use one restroom and females should use a different restrooms are bigots. In fact, she’s using bigots as shorthand for “people who have a different opinion than mine”. We’ve reached the point where calling someone a racist, sexist, homophobe, bigot and so on doesn’t have any effect because the terms are used so casually.