Do you like iCloud or other Apple services? Use them? Have an axe to grind with them? I can't tell.<shrug> People can put their heads in the sand about that all they like, and whine about what Apple (and Google) do or plan to do. I fail to understand why fools continue to expect privacy on systems they do not control.
While Apple's services history/rep isn't great and I'm not claiming it is, Family sharing works for me without sharing my entire keychain. Has since the feature was introduced. Obviously, it is broken for others. If it broke for me in this particular way, I would also turn it off...but I would also explore all my options that could close the security hole while enjoying the functionality I had.
I imagine that the OP and others that came here for help are interested in how they might be able to get from their broken state to the happily working state that myself and others seem to be enjoying. They want to use Family Sharing and keychain together without leaking credentials, which is obviously possible.
I fail to understand how you think it's helpful or constructive to tell those experiencing issues just to use something else (well, that and a couple of unnecessary pejoratives). Everyone has a different risk calculus. Just because one might seemingly believe that Apple's services will always be irretrievably and hopelessly broken on an infinite timescale, it's not a unavoidable certainty. Again, keychain and family sharing work for some without this specific issue, so why shouldn't others try troubleshooting it, in case it's an edge case that can be avoided/rectified? Would you tell someone who was trying to fix a current flat to just buy a car with better tires, and they made a mistake getting the car they have and should have never considered it?
Tell me, if the presumably rock-solid, privacy-preserving system(s) you use broke down, would you try to track down the cause and try to address it, or would you just think "Forever Compromised!" and immediately move on to the next thing?
Just like your system has the potential to break, Apple services have the potential to work. You personally don't want to risk it? I support you doing you! Going around telling people that their approach is fundamentally wrong instead seems like wasted energy. As is spending your time reading "fools" "whining".