According to Wiktionary, rock music is;
1. (music) Any of various genres of popular music employing electrical amplification
"Rock" is far too wide a genre to be able to collectively explain any of it, and the generally accepted rule that the higher the din, the more rock is wholly untrue.
As far as I'm concerned The Beatles are just as rock as Led Zeppelin, The Rolling Stones, The Who, etc.
The same goes for Queen, even in the sense of making a lot of noise, Queen were (and are) very much one of the heaviest bands going. Yes, they came out with tracks like I Want To Break Free and A Kind Of Magic, but in the early days they were referred to by the major publications as a heavy metal band. Check out Liar, Stone Cold Crazy, Sheer Heart Attack, Brighton Rock, It's Late and Death On Two Legs (Dedicated To...
With regards to The Beatles, Ticket To Ride may be mild by comparison now, but back in 1965 that was about as cutting-edge as a track could get, with it's very unique and exciting percussion. Helter Skelter, Revolution, I Want You (She's So Heavy), Tomorrow Never Knows, Rain, the list goes on and on.