During the torrent of backpedaling and "context mongering," if that's a term, the word "joke" came up toward the tail end of the discussion, used in such a manner as to imply he may well have had no sense of humor or any understanding of how telling jokes is supposed to work.
The late George Carlin once said, "Even rape can be funny." and, in principle, I agree with that sentiment completely. If my saying that is making your blood boil or getting your head all-a-shakin' over it, I understand completely and don't blame you for it. However, I'd like you to read that sentence again, emphasizing the words "CAN" and "PRINCIPLE." As an artist, I believe that boundaries and rules are made to be pushed, bent, and even broken. This applies to comedy as well. It's not uncommon to see one comedian met with a standing ovation for the same reason another may get booed off stage for telling a similar joke. I've seen one comedian build an entire routine about the sorts of tactics terrorists should be using instead of bombings and hijackings, the audience eating out of his hand the entire time, while another cannot even get past his opening line of, "You know what I love about terrorists?" without the entire house calling for blood.
Why one routine got cheers while another got jeers can generally be chalked up to luck and timing. Some crowds are a little more forgiving of having their buttons pushed than others, some subjects are best left to simmer a bit before the roasting can begin, and what separates a good comedian from a bad one is how they handle being dealt that bad hand. Stand-Up Comedy was once described by the late Mitch Hedburg as, "the noble profession of convincing a roomful of strangers that you're funny." going on to mention that you can't please everyone all the time. The fact is, barring any open mic night at a local gig, by the time you see a comedian perform on stage, they've gone through their routine dozens, if not hundreds or even thousands, of times before to a variety of crowds in a plethora of venues. During this time, jokes are either refined or dropped altogether.
Sometimes, you tell a joke, and it doesn't go over well. Either people don't get it, or worse, they don't think it's funny. At this point, any good comedian knows that quite possibly the worst course of action to take is to defend the joke and insist on its brilliance and edginess. Sure, sometimes a quick quip or well-worded jab can bring an audience back from the edge of the Great Booing Chasm, but the general rule of thumb is that if the audience doesn't laugh the first time, it's because you didn't tell the joke right. As such, explaining it, defending it, and insisting on its merits will never win back that lost first laugh. Not only do those people get booed off stage, but their future in the profession is non-existent.
There was a post on Facebook some time ago that illustrates this perfectly. It was a panel from a comic wherein iconic supersonic crime-fighter The Flash exposits the extent of his exceptional acceleration by describing occurrences that can only be observed in the space of an attosecond. The rest of the post explained exactly what an attosecond is. Informal definition: there are more attoseconds in the time it takes to say the word "attosecond" than there are grains of sand on all the earth's beaches. One of the comments to this post was, "Dude could rape a b---- and she wouldn't even know it!"
As you might imagine, quite a few people were offended by this remark. I wasn't offended by it personally, per se, but that's not to knock everyone else who called him out on what he said as sexist and insensitive. They'd every right to be offended, though it seemed more people simply didn't find the joke funny. I thought, "Dude went for the low-hanging fruit. Whatever. Swing and a miss." and that could have been the end of it. Some people got mad, some people didn't laugh, a few clever folks satirically pointed out the logistics of such an event occurring (friction, combustion, and all that), and the joke was generally received as being in poor taste.
Except that wasn't the end of it, because the idiot who laid that egg felt he was entitled to a laugh, and damned if he wasn't going to leave the discussion without changing at least one mind that his joke was the funniest thing in existence. The point is, him apologizing for the joke may have been unnecessary (courteous, but unnecessary), yet defending it and insisting himself beyond criticism for it puts him well beyond what even the sincerest apology would make amends for. I shouldn't have to explain the limitations of freedom of speech any more than I should have to explain how unrealistic and downright naive it is to insist every joke told receive the same equally positive reaction.