I am not even sure, if I am getting this right. If I embed an iframe in my website, traffic from Tor users will get tunneled through my user visitor's IP? How does consent works with relay.love? Does my website vistor's IP show up as TOR exit node?
That example has the users consent before starting.
"If you don't control the routing, you're being routed."
To be fair, ProtonVPN allows you to export their config. It seems to be an exception to your rule.
However, it should be noted that this mechanism doesn't just allow remote sockets to be created through Javascript. It can only communicate with other servers that either use some version of WebRTC/WebSockets or plaintext services that ignore the extra protocol overhead as garbage and happily parse the rest (some IRC servers and WebSockets are a nice example).
As you can see in the technical overview, people use peer to peer technology to connect to your browser, which then uses WebSockets to communicate with a WebSocket server for a normal Tor entry point.