Who said the word woman has no meaning?

It does.

But the meaning is contextually fluid, somewhat. Come on, if it had no meaning, you wouldn't see people using it. The difficulties with women's sports will get ironed out in time. You're not a woman athlete, so you don't have a pony in that race anyway.

Perhaps it doesn't bother feminists as much because our lives have a natural fluidity to them anyway. And that's been weaponized to dehumanize us for eons anyway, in a multitude of ways.