There's a huge leap between using the platform and giving them all of your data. Be restrictive around what you put up, and the permissions you give it. Sure, it's some measure of personal involvement, but it's necessary for the most basic of access.

Shouldn't it also be the case that, if you're the one not on a widespread platform that - clearly - a lot of people are using to communicate, it's on you to make the effort to reach out?

I actually think the opposite of your claim - expecting a family who's member has committed suicide to have to actively reach out to this one person is rude and without depth. Expecting any kind of personalised treatment whilst alienating yourself is similar, but that one example sums it up for me.