I don’t run any forums at the moment, but when I did, the software I used gave users massive opportunity to provide information about themselves. Some users loved this and filled in every field, perhaps because they enjoyed that it made socialising easier.

The problem for anyone wanting to host a forum is that using off-the-shelf software is a sensible route, but the available software might still be leaning towards offering to collect data like this, might not yet have support for GDPR disclaimers, checkboxes, etc.

What I’m saying is let’s assume neither malice nor incompetence and instead that those wishing to host forums may be hamstrung by the available software.