> What I don't get is why the industry has decided to force encryption with HTTP/2?

For reliability and success of the protocol. "Reasons for choosing TLS-only include respect for user's privacy and early measurements showing that the new protocols have a higher success rate when done with TLS. This is because of the widespread assumption that anything that goes over port 80 is HTTP 1.1, which makes some middle-boxes interfere with or destroy traffic when any other protocols are used on that port." (Source: http://http2-explained.haxx.se/content/en/part5.html)

Believe me, TLS is very much necessary in practice here.