This was a long time ago (7-10 years), but 1and1, Hetzner, OVH, HostGator, LiquidWeb did not allow IRC hosting. They were the cheapest, tbf. I only use Linode now, haven't looked into it.
I am certain that Linode won't give you any grief as long as you make some effort to keep botnets from abusing your service.
I've personally checked with our Network Operations team, and ran a test with a teammate. We do not currently block IRC ports.
It’s the DDoS attacks they didn’t like dealing with, but I suppose that’s one way of describing it.
I can't speak for the other services, but we have a very active IRC channel. I run my IRC instance off of a Linode I created just for that purpose.