Given it was reported to the police, the police investigate and the CPS prosecuted and a jury of peers found him guilty, it would appear that yes, it is a homophobic gesture that has caused offence.
As for dishing it out and not taking it, I might often agree with that sentiment when it comes...
Of course it's an extension that works. You make the claim that since most of the crowd isn't gay, no one is really hurt by it. ("It was an infantile gesture to the crowd most of whom I presume were not gay so not sure where the real hurt is."). If your argument is the insult doesn't apply to...