So I was completely wrong about this. More details tell me that this is a deliberate attempt by Ken to block any and all VPN access to OF. The site does load if you access it without any sort of VPN in between you and the server. It even stopped my wireguard tunnel.
So how is this happening? Possibly the same way cell phone networks detect tethering usage: by checking the TTL against an expected value. I have not tested this theory, but if this is how Ken's developer is doing it, it might be possible to change your system's TTL up or down by 1 and bypass the VPN check.