@_elena As per the op the public nature is an inherent of the design and it is even up to an app to respect or not (so someone could write a block-ignoring app, like the one you pointed out).

Since blocking for any reason or none is part of the culture there (imho a great thing), one could perhaps camouflage any particular block with volume, say by using block lists.

Of course people can still look for specific blockers for abuse, but there's a good chance many others are also blocking them..