Because 'women' is only a noun, and it is used as an adjective in the title.
You can gramatically say 'Two women played a pivotal role in the..." or you can say 'Two programmers played a pivotal role in the...", but you can't, at least to my ears, cleanly say 'Two women programmers played a pivotal role in the...'.
What sounds more correct to you?
"I saw two men teachers at the ceremony", or "I saw two male teachers at the ceremony"
I'm sure we can just use the former language to the point where people recognize both as equally correct, but as it stands currently, most English speakers would far prefer the latter over the former.
You can gramatically say 'Two women played a pivotal role in the..." or you can say 'Two programmers played a pivotal role in the...", but you can't, at least to my ears, cleanly say 'Two women programmers played a pivotal role in the...'.
What sounds more correct to you?
"I saw two men teachers at the ceremony", or "I saw two male teachers at the ceremony"
I'm sure we can just use the former language to the point where people recognize both as equally correct, but as it stands currently, most English speakers would far prefer the latter over the former.