It's something I've been noticing for a long time. Getting a Muslim to condemn an offense committed by a fellow Muslim against an "infidel" is extremely difficult. A skilled Muslim debator will dance around the topic, attack the questioner, try to shift the debate onto "what these other guys did to those guys", issue vaguely worded statements saying "it's not nice to do bad things", and most people won't notice that the Muslim never did quite make any explicit statement of condemnation against his fellow Muslim.
Now, a Muslim can safely condemn a Muslim for being insufficiently Islamic, or for being inadequately energetic in fighting the infidel -- that's OK, he won't get into trouble for that. And a Muslim can criticise another Muslim for an offense against a non-Muslim IF that offense caused trouble for Muslims -- notice the distinction, he's not condemning the offense against the infidel, only the fact that the offense resulted in problems for other Muslims.
The verbal dancing can be amusing