I'd like someone to tell me what you feel about the english sentence I got from
an anime's subtitles unlicensed yet.

"Human men are rougher than I realized."

The original japanese lines of it is 人間の雄は想像以上に下劣ね。.

My questions are

1. Isn't "than I expected" commoner or more natural than "than I realized"?
2. Why is the "Human men" plural? I thought it's just because she said it in general

terms, though.
3. Doesn't the meaning of "human" and "men" overlap?
4. If I write "Human males" instead of it, what do you feel about it?

The character speaking is not a human, and got the impression of human from
only a man. In addition she has a pride. The translater may be not a native english
speaker, but i don't know much about it.

I'm grad if you modify my wrong english, too. Thanks