If that room were--say--the ladies' restroom, then yes, I can very much imagine a situation where such a thing were very clearly sexual harassment.

That's none of your business. How people "describe" sexual harassment in casual conversation, is not how sexual harassment is judged against policies, rules, and in common-sense consideration when evaluating punishment for making choices that violated another person's boundaries.

Frankly: if the dynamic between two individuals is as such, that for one to walk into a room has been plainly stated to violate the imposed boundaries of another, THAT is harassment. Textbook. Harassment. That's what restraining orders are for.