You're not wrong, but I think the point was, in a browser, you can get your TCP _connection_ "automatically" encrypted by connecting to HTTPS endpoints. It's not so easy -- "built in" -- with a connectionless protocol.
(Even so, it's not that the "TCP session" is encrypted; it's that the transport-layer security mechanism encrypts the payload of the TCP session. The metadata for the session--the respective IP addresses, sequence/acknowledgement numbers, and so on--is still in the clear. I realize that, at this point, I'm being quite pedantic but I'm a networking person at heart and I want software developers to better understand the infrastructure that's being used.)
Most implementations (eg. WebRTC) involve pulling in truck loads of C libs; it's insane. And then you want to support other clients? Good luck.