Weirdly I've got the complete opposite view on the relative importance of those two kinds of data.

I'm happy to have my blood type public so that I can get the correct transfusion if I'm in an accident and maybe it will save someone else's life. It's info that could easily be stolen once and it's not like it's ever going to change so once it's gone it's gone. If there is an opt out organ donor system then there is no shortage of donors and no "organ poaching" (I'm not really sure what you meant by this).

My private conversations on the other hand are mine and mine alone and should be no one else's business. There is much damage that can be done to a person with the contents of every chatlog/call they've ever made.