Allow me to vent my fevered spleen:
1. How in God's name is it strange? It's a firefight we're talking about here, not a game of chess. Never mind the fact that we're all yakking about second or probably 15th hand reports.
2. The Muslim Brotherhood have been around since the 70s, and have been anti U.S. the entire time. They are also Marxist influenced and thereby dingbats. The fact that they have a big following is hardly news. So what exactly IS news about this? The article you linked to seemed more interested in provoking alarmist flapping than providing useful warning of anything.
It seems strange to throw a grenade inside a building when trying to rescue hostages. And I did say we need to wait till all the facts are in. And Muslim Brotherhood is Marxist influenced? That's a new one. What is news? They declared jihad against the US, that's the news, much as Al Qaeda did before 9/11. That announcement is certainly related to the situtation in Egypt, that's another major angle on this. Also not everyone here is as well informed as you, so I thought the article provides quite a bit of interesting info people may not be aware of.
And yes, there are a lot of radical Islamist groups, but on closer examination virtually all of the non-Shiite ones either sprung from or/and have close ties to the Muslim Brotherhood, Al Qaeda being one of those. The main difference are the tactics, which are complementary, Al Qaeda's being open warfare, Muslim Brotherhood's long term subversion till the time comes.