The argument that the majority of Muslims are peaceful is correct
And how do we know that? Seriously. To me this is a variation of the argument that the problem is just with a "small minority" of Muslims. I have yet to see any real basis for such statements. They are just made as though they are self evident. And they're not.
Let's take this statement:
"If someone insults the Prophet Muhammed, they should be killed."
What percentage of Muslims worldwide agree with that Statement? I'd say we don't know. I'd also say I wouldn't be surprised if the majority of Muslims worldwide would say they agree with that statement.
What about the idea that the entire world should be converted to Islam by violent force if necessary? Do we know how the majority of Muslims worldwide feel about that?
Again, I suspect that the majority of Muslims worldwide DO believe that the entire world should be converted to Islam by violent force if necessary.
I don't have the polling data to confirm my belief. But I don't think those who believe otherwise have the polling data to cnfirm their belief either.