When comedians say things like this, it's almost always about manipulating their perceived status relative to the audience. That's why you'll see him say the opposite in other situations. It's all just playing games with status. To make different bits work, comedians either need to be perceived as higher or lower status than their audience, to garner the sympathy/revulsion needed to make the surrounding material come off properly.

EDIT: came up with a better way to state this: sometimes you need to be the underdog, sometimes you need to be an alpha-asshole.

Here is the superb Stewart Lee talking about this issue in a recent interview about his new series, which is mostly his standup:

What was Chris Morris's input as script editor?

"He really helped fix a particular problem. I noticed reviews saying that I was arrogant and condescending. I thought, 'That's interesting because it doesn't feel like that live'. In the room I'm able to fabricate some kind of struggle whereby the gig isn't quite working. I'm a lower-status character, so when you criticise someone you don't do it from a position of authority or strength - it doesn't seem arrogant."

How did Chris fix that on screen?

"I wanted some sort of device that would lower my status or make me appear to be under pressure. I spent days on end talking to Chris about different ideas to get that to work. We ended up with Armando Iannucci interviewing me throughout the series in a hostile way - criticising all the material and my role in the programme. That's cut in with all the stand-up and it works really well."

Here's an example: http://www.youtube.com/watch?v=r2-qqtvsNDI

Very few people can manipulate a room like Stewart Lee.