Wasn't the idea with Alf Garnett, increasingly over time as society changed for the better, that he was always in the wrong with his bigoted ideas and he always came off worse because of them? Of course you'll always get thickos who take it at face value and agree with the character and laugh with him rather than at him. A bit like all those Americans who thought Born In The USA was a patriotic anthem.
Maybe the Paul Chowdhry question is similar to the question of why it's not ok for white people to say the N word but it is ok for black people, having reclaimed it from the slavery days. Dunno. Things are getting complex (or another word might be sophisticated) nowadays, because we're gingerly inching our way back from PC, which can be a bit worthy and joyless. So you've got the "ironic" bigotry of Ricky Gervais, Jimmy Carr, etc. It seems to be alright to laugh at the Chinese accent again lately for some reason. It doesn't sound very ironic to me, but opinions vary on the matter. Personally I reckon it's dodgy. Ha ha those different people with their hysterical different way of talking.
The idea with this ironic bigotry is that anyone reasonable with a brain knows what's a fair attitude and what isn't in these enlightened times ( ! ), so we can relax a bit and just laugh if something's funny. Personally I find some sexist jokes are funny, for one thing because you can often turn them on either sex. Most racist jokes I come across, maybe texted around, aren't funny to me, not because they're racist but because they're made up by stupid people. They rely on a dumb, inaccurate pretext, whereas jokes are usually about the surprise revelation of a truth. There are race jokes that aren't racist, and they're much more satisfying. What do you call a black man flying a plane? A pilot you racist cünt. That's bloody clever that, because it makes the audience try to think up a racist punchline and then chastises them for it. (It does need the big expletive on the end, switching one unmentionable for another.)
Personally I think Louis CK is very funny and interesting on these matters. Put "louis ck n word" into YouTube and read on.