No, I think that dogwhistling about Islam is an underhanded method of going about it. I think that if you talk about Islam, genuinely, then you can get somewhere. If you just want to slam it, then you play the game - by the way, please note, they said this. Not "They are part of X radical group, etc." Using coded language, or throwing it in as an aside rather than addressing it is a way to lead your responses to the point you want, rather than being the one to state it yourself (general you)
For example the way you phrase your last statement suggests you think that Islam itself is the problem, and that it isn't really being misinterpreted. I don't know whether that's your thought, but it reads that way to me. Had OP said "I think this is another example of radical Islam" or "I think all Islam is responsible for this." Whether I agree or not with the content, the method of conveying that content is at least honest.
Tl;dr: It's how things are said, not the content of them that I'm discussing.