You only have to look at how the Press is treating him.
It's depressing. We've probably got 5 years of this to come. I'm not sure what these right wing types are on but Corbyn doesn't strike me as a far left person. He's more an old fashioned Social Democrat and we need more of them.
The blanket coverage and the constant monstering could be starting to backfire. Channel 4 News interviewed a veteran who thought that Corbyn had been pretty resppectful. far more respectful than the Sec of Defence, Phillip Hammond, who admittedly was singing but was also visibly seeking out any Press/ TV cameras. Commentators on the newspaper stories also have been quick to point out that quite often the Press don't give a monkey's about the royals when it suits them (Diana, Nazi stories)
Other pictures have emerged that show a number of people not singing, some of them stood right next to Corbyn.
Ed Milliband wore a smart suit every day and no doubt sung the anthem with gusto. It didn't make any difference to the way he was portrayed in the Press.
All this ludicrous ranting by the right wing media hopefully will backfire. Remember what happened with that Demon Eyes idiocy that the Tories ran before the 1997 election?