Its similar to the arguement started by Alf Garnett. Warren Mitchell used to say people would come up to him saying "I love that Alf- he's dead right, send 'em all back", to which Mitchell would reply "Actually its people like you we're taking the piss out of".
All well and good and very noble, but if the general public miss the point and run with the wrong idea, then damage is done.
The gay war reporter doesn't really come out with any jokes- he is just a (fairly realistic) very effeminate man andthat's supposed to be what we should laugh at, and that surely IS homophobic. The gay Nazi is a cartoon, but its not parodying a style of comedy like Reeves & Mortimer did on occasion, Al Murray is serving this up as a comic character and we're supposed to laugh at it in its own right. Its clumsy, the jokes are feeble and its just rubbish. Its not overly offensive, just crap.
Is it just that straight men, acting the role of a gay man, become offensive? Eric McCormack showed that's not necessarily the case, and straight men can write camp comedy as Barry Took & co showed.
But with Will and Grace, its interesting that they didn't use a straight actor for the character of Jack-that's the line and I think that's where Matt Horne, James Corden and Al Murray get it horribly wrong. The 'stereotypical' Jew seen in comedy is performed by a Jew- if a gentile did it what would the reaction be?