Very unfortunate news. I hope they realize what a mistake this is and reconsider!

I am disappointed as well. The web interface is sluggish over a VPN.

I don't know what people expected. Why would you leave IRC/XMPP to go to a walled garden?

Nowadays, alternatives exist like matrix.org with an open protocol. If usability was the reason you weren't on IRC, take a look at matrix.org.