"Defeatist ring"...No, just not willing to go "jousting at windmills".
It's really not up to me to fight FB. There are people far more able and willing to take up the challenge... and some are already working at it. There have been recent changes and cancellations of accounts for various rule breaking.

As for "...perhaps the platform should be dismantled into smaller-size pieces ..." I can't even imagine what that would look like. It's not like making some financial conglomerate divest various pieces. It is one entity/algorithm with Zuckerberg holding the strings.

I am reminded of threads from several Mudcatters saying "Why doesn't the USA DO something about those ridiculous gun laws?"
I have spent far too many hours typing detailed reasons why it is so hard.
   As a couple have said above, FB has several virtues, and those who want to avoid the real crap can mostly do so.

No.. it's not a matter of being a defeatist, but rather being a pragmatic realist.