Anecdotally I think this is true. My kids and their friends (all zoomers) are not active on X / Facebook. They occasionally browse those sources but rarely ever post.

I think it has to do with "whats the new thing when you are 18" - for millennials that was social media. It makes a lot of sense to why social media was the first to go "woke", because its user base was all 16-20 yr olds who were all set on changing the world one post at a time.

I see some similarities between Gen X (my gen) and Gen Z. Both of our generations had very politically active older generations we followed. In Gen X's case, I think we felt some degree of suspicion to the Boomers political advocacy. Not that we necessarily disagreed from an ideological standpoint - just that it wasn't our thing and thus retreated from advocacy a bit.