Here's AA Gill's original quote:-
Which brings me quite naturally to Clare Balding on a bicycle in Devon. Some time ago, I made a cheap and frankly unnecessary joke about Clare Balding looking like a big lesbian. And afterwards somebody tugged my sleeve to point out that she is a big lesbian, and I felt foolish and guilty. So I’d like to take this opportunity to apologise. Sorry.
Now back to the dyke on a bike...
Maybe you're reading that quote in context, and still don't get the joke. Let me try to explain it to you...
1) Gill called Clare Balding a big lesbian.
2) Some people complained about this despite it actually being true.
3) Gill uses irony to express guilt over saying something which is true (because you shouldn't need to express guilt over saying something that is true).
4) Says something that is quite deliberately designed to juxtapose his already fake apology by saying something even more offensive on the same subject.
If you can't grasp that, then you should probably add some tequila to your breakfast and lighten the fuck up.