I don't see anything in Sacco that says "we should not offend". I think Sacco's piece as a whole says three things, and I think that Bolling agrees with the first, rebuts the second, and ignores the third. From the tone of your question, I infer that you're asking me about that "third", but I'll just get the first two out of the way first.

First: Of course we should defend free speech! (Okay, good, glad we got that out of the way. We all agree, yay.)

Second: CH is "tweaking the nose of muslims", and that's "vapid". (Bolling says that's not what CH is doing. I have no idea if Bolling is correct, but it seems plausible. So let's assume Bolling has rebutted Sacco on this.)

Third:

Thinking critically about geopolitics would be more interesting and constructive than "tweaking .. noses". There might be geopolitical and sociological reasons why there exist so many more Muslim-affiliated suicide bombers than there are first-world/modern/white/Christian/etc suicide bombers.

Maybe the issue isn't that Islam teaches violence. I mean, there are plenty of exhortations to violence in Christian history, in Western history, in "modernity". And my understanding is that much of the Quran and the Hadith is calls to peace and non-violence. So what's the deal? Maybe the issue is that there's a lot of inequality in the world (and the inequality is actively pursued by the empowered, not just an accident), and this breeds resentment, and breeds tribal thinking, and Muslims as a group have relatively little overlap with the empowered class (House of Saud notwithstanding). Maybe that sort of us-vs-the-West tribal thinking is the only source of empowerment that certain people can find in their lives, and some tiny fraction of them are borderline-insane young men who jump over the cliff into insanity and strap on vests. And if that's all true, sure it's easy and correct to say "no matter what their excuse, suicide bombing is evil". Fine, I agree. So what? Given the choice between labelling a past murderer as "evil", or preventing a future murder, which is more important to you?

If we agree that violence and terrorism are a problem to which we'd like a solution, what forms of solution can you imagine? Can we realistically eradicate a religion? Alternately, can we realistically eradicate the spectrum of extremism within a religion? How about can we build a police state that will actually prevent this kind of thing, and if we can should we? Or can we just wall off all the crazies and not let them into our countries, and if we can, should we (with the collateral effect of maybe walling some innocents in with the crazies)? Personally I think the answer to all four of those is a very obvious "No". So do we have an alternative? I don't know if an alternative exists, but I suggest that if it does exist, then reducing inequality seems likely to be a prerequisite.

The last two paragraphs of mine are an attempt to spell out the last two panels of Sacco's strip. "We can try to think about why the world is the way it is, and what it is about Muslims in this time and place that makes them unable to laugh off a mere image. And if we answer 'because something is deeply wrong with them' - certainly something was deeply wrong with the killers - then let us drive them from their homes and into the sea. For that is going to be far easier than sorting out how we fit in each other's world".

So, in summary, Sacco's third point as I see it: Yeah yeah we all agree in free speech, but maybe if we stop foaming at the mouth about how evil a group is, and cultivate some empathy, we can find a solution that doesn't amount to genocide.

On a personal note, I find it very hard to have empathy with religious people of any stripe. But I am well aware that my position on religion makes me a very very tiny minority.