Quad is a gold medal standard, yes, but the current system of judging has removed emphasis from the jumps and spread it to all other aspects of the program. Evan's program was far more difficult than the programs in 1988 because the actual choreography/spins/footwork was much more demanding. Jump-wise his program wasn't particularly difficult, but in terms of the overall program it was better than Plushenko's (even Irina Rodnina acknowledged that Lysacek was better). While Plushenko focused on his quads, the other guys focused on their programs.
The point is that when you say "It's not men's skating without a quad", it shows a sense of entitlement to winning and instead of being gracious in defeat (especially when he already had an Olympic gold medal), he decided to complain about it.
And I wouldn't attribute the quads we see today as Plushenko and others protesting. The value of quads were slightly increased, but you got skaters doing them much more consistently (like Chan, Fernandez, Amodio, etc.). Chan had actually planned to do quads at the Olympics but a year of injury set him back a season (hence why he was consistently starting to land them the year after Vancouver).
P.s. if it's not men's skating without a quad, then should Plushenko's quadless Euros 2013 SP and Euros 2012 SP not be considered "men's skating", by his own words?