You can be upset about it, but humans are dumb. Language is dumb. Terms that people have came up with, the definition that has changed over time, and how it does not relate to things in the present is dumb. Nothing will ever be exactly how you or anybody else wants it to be. It's a collective that you just have to accept as it is.

That being said, feminism has old roots when we used to pump our wives full of lithium and give them lobotomies. Treating them as equals was not something that was even discussed. You could say you were an egalitarian, but then you would have to also admit you liked people of color, or LGBTQ people. And that was a step too far for some.

Also its not excluding half the population. It's INCLUDING them. Men are included by default. It's a term that allows the conversation for how shitty women are typically treated to exist.

One side has all the power in this scenario. Men will always have innate physical capability that outstrips that of women. As such, it is impossible to consider search of equality between genders as anything other 'feminism', as men are the only ones with the implicit ability to subjugate the other. Women do not have this implicit ability over men. There is a reason that it's called feminism which is that women are always the ones being subjugated.

Besides that, feminism is good for men as well. By exploring concepts such as the all-encompassing gender matrix, what it is, and how it is embedded in and affecting society, it can be shown the damage that such concepts do not only to women, but to men as well. For example, why is it considered 'girly' to have strong emotions other than anger? This affects many men's lives in negative ways. Now what if I told you that the "all-encompassing gender matrix" is just a term I used to make patriarchy more palatable to you.

You can say that feminism inherently unincludes half the population, but only because that half already has and has had the vast majority of power in society since pretty much the advent of agriculture, but it could be argued even before then as well...