> Their cause is to universally redefine "woman" to include men who desire to be women, and "man" to include women who want to be men.

This is a reductive view that presupposes gender as a pre-existing discernable static fact of a person's biology as opposed to an apparently extant human phenomena. The idea that they are the same is a profoundly simplistic view of the issue, one not supported by modern psychology or human archaeology, littered with happy societies full of folks we would now consider "gender non conforming". It's not a new cause, nor is it attempting to "redefine" anything.

> We can already see the effects and they're not good

People living authentically is great, actually. Respecting others and their preferences, also good. It genuinely doesn't hurt anyone. The effects to my life are roughly equivalent to my friend Phillip telling me he prefers Phil.

> harmful to women and girls in particular.

In very hypothetical, "just asking questions" ways that have yet to be borne out in any sensible reality. What has happened many times is cis and trans women being harassed for baseless, paranoid reasons. It's especially repugnant a defense when you consider that trans folk - trans women in particular!- are among the most vulnerable to attack and abuse.

If we were worried about harm to women and girls in a tangible, meaningful sense, we would be quick to punish actual perpetrators of verifiable assault than play feminist only when we find a more vulnerable throat to crush.

It's like I can't win. If I behave too feminine as a man people give weird looks to me and mockingly refer to me as a woman. A significant portion of the society still does not think men should be very effeminate.

So I am like ok, sure, I don't care much about this gender ideology, but if society does not think I am a man, then I am a woman!

Then people are not happy again. They call me a man who just wants to become a woman.