I've never noticed any change in my mood due to my period. If somebody insinuated or said the way I was acting was due to being at a certain point in my cycle, I would not be impressed.
I think it's insulting to assume that's hormones are the reason somebody is acting a certain way, no matter what their gender, because it's a way of dismissing their feelings or behaviour. I think this is especially true considering the sexist context these kind of comments usually exist in, I've only ever heard people use this kind of talk in a derogatory way.
If somebody notices that they personally get moodswings due to hormones, it's fair enough. If they want to explain that to people, and in the future they put their behaviour down to hormones, that's fair enough. But I think it's an insulting thing to assume. Lots of things can make a person act "unreasonable", they might be other wise upset about something else, they might have had a really bad day, perhaps the topic is something emotionally close to their heart, maybe - just maybe - they're not actually being unreasonable at all, perhaps you only perceive them as being unreasonable because you disagree with them or have a different experience/opinion than that.
Anyway, I came here to say, I just don't "get" eurovision and I have never watched the whole thing.