The fact that these organizations constantly emerge from your community suggests that no matter what you or others may say, they represent at least one expression of Sunni Islam.
Another fact is that the non-Muslims too nearly say the same thing; that these organizations constantly emerge from your religion. However, we know that at the end of the day, these are claims that carry no weight whether said by a Shia or non-Muslim.
Also orthodox Sunni usually don't back up their denunciations of groups like AQ or ISIS with conclusive evidences from their own books. Perhaps it is because they haven't got any.
Let me not go too far and allow my teacher (whom I personally know and put questions to) answer you. This man alone held weekly seminars (over the weekends, stretching months across the year 2015) to teach Muslims the correct aqeedah (so that they are better prepared not to fall into extremist ideologies) and introduce Islam to non-Muslims (including law enforcement agencies).
Judging by that standard , though, it is clear that Sunnis don't have any real grounds on which to denounce ISIS and groups like them.
I think you have been provided evidence which is not only rooted in "real grounds" but one that is first-hand. In other words, this is one scholar I know who has taken it upon himself to condemn these groups. He is one of the many in the Washington DC Metropolitan Area. There are many more like him.
Essentially, I don't think it is accurate to say that they are not an Islamic entity. Clearly they are not Hindu or Christian. I think they are Sunni Islam taken to a logical conclusion.
And what is that logical conclusion?
so I have to regard them in some sense as Muslims as well.
Oh, so now they are Muslims, according to you? The flip-flop and the art of making up rules as you go along! Now that you are forcing them upon us, you have no choice but to say that they are Muslim while your scholars are calling them the exact opposite.
I don't want to unite with people who consider me an apostate and who want to continue to steal from me and to kill me.
You are not an apostate. Refer to Dr. Tarek Elgawhary's aqeedah lectures.
Sunnis provoked this war, and until they are subdued I don't want to talk about unity.
Which war? I hope you have a far-sighted view and not restrict history to the time from where on ISIS came into existence.
I acknowledge what your teacher is saying, but his point of view does not represent some sort of consensus among Sunnis. Whether you like it or not ISIS, AQ, all of them, emerge exclusively from your community, and even if they don't have unanimous support, these groups are very adept at using sources from your own books to back up their actions. So at minimum they represent at least one faction within the Sunni Islamic world. Nothing you say is going to refute that. Unfortunately, non-Muslims in the West are usually too concerned about political correctness to emphasize this fact, but to the extent that they blame the problem on your community, they are right.
I never said Sunnis are not Muslim, so I don't get why you're so surprised by my statement. I think much of the reason why everyone is takfiring each other is because Muslims, Sunni or Shia, always want to have a religious justification for war. I don't have that problem. My problem with Sunnis is not that they are not Muslim, it is that they want to kill me.
"Which war?" You act like the entire post-colonial Arab order hasn't been rooted in oppression of Shia, and theft of their natural resources. Or that Sunnis didn't constantly massacre and invade Shia. Or that Pakistan hasn't been smacking the Shia around consistently since 1977. I'm not even counting Zarqawi and his ilk, who initiated the current war in Iraq.