[brazzy]

Possible answers:

1) Some political views correspond strongly with problematic behaviour that a conference would rather not deal with.

2) Virtue signaling for PR purposes.

[bryanrasmussen]

2) would require the conference organizers to announce we've blocked this person.

[brazzy]

No, just to announce that they are blocking based on criteria the audience agrees with.

[akvadrako]

An announcement would signal the wrong thing. Better to just let some people become aware of the existence of blocking.

This is kind of like considering an "anonymous" donation more deserving of praise than a public one.