I feel you didn’t read the original post. It isn’t about expecting privacy, it is about understanding how it is maintained on a federated platform.
Many users coming from other platforms do not understand the mechanisms here and how they are different. Take a look for the comment here about vote privacy, which many assumed was private due to coming from a platform where this was.
So, obviously an anti Lemmy bias there, and not entirely true, but there are some aspects of federation it can be dangerous to ignore.
There is a different primary privacy focus here, and it provides an extreme level of privacy but places an extreme level of responsibility on the user for their own privacy, more than most places.
There is a distinction to a potential scrape and a system designed to duplicate, often irreversibly at submit.
There are also other things people are often not aware of and the community is not doing a great job communicating. Admins are not doing a great job of protecting themselves either.
For instance many, still don’t know votes here are entirely public.
If you understand this all and are comfortable, great. Many do not prepare themselves and would engage differently if they had a better understanding.
For a take by someone who is pro-federation but not ignoring these concerns see: https://lemmy.ca/post/948217