Oh please: Letting a user block another user has nothing to do with a free and open internet. Save the anger for when there’s an actual threat to the internet, otherwise people will just start tuning free/open internet advocates out entirely.
It is quite bad really. One feature seem to be to single out users so they can't hear you in a group chat. To me that is highly toxic. Speaking behind someone's back, to everyone. It will be used for bullying of anything.
Why do you need to be able to force people to listen to you for the internet to be "free and open"?
Bizarre takeaway. AIM and MSN had the option to block people 20 years ago and I'm pretty sure IRC had it even before that. It's not a new concept.