แปลว่า:We support women.
Yep, agreed. I've noticed a few times in this course they've tried to emphasise pluralisation by adding something like "หลายคน" to the end. But like you've mentioned, adding it to the end of "ผู้หญิง" makes it sound more like "many women".
I feel as though in Thai this sort of pluralisation is implied by context:
- ดิฉันเป็นผู้หญิง = I am a woman
- ผมชอบผู้หญิง = I like women
And I feel the sentence in this question relates to that 2nd example, i.e., simply using "ผู้หญิง" (without the extra "หลายคน" at the end) would have been sufficient.