|I find typically that Human Rights organizations show an asymmetric bias between state vs non-state actors. This to me, is akin to "Deep Pockets" Theory, whereby most blame is shifted to the largest party in a conflict, independent of their relative conduct.
The classical case for Deep Pockets Theory: There was a story of a man making a phonecall from a payphone on a street corner. A drunk driver came careening down the street, jumped the curb, and struck the phonecaller, injuring him. In claiming compensatory damages, the injured man couldn't get anything from the drunk driver, who had no money. So instead, he sued the phone company, which did have a lot of money.
The example demonstrates Deep Pockets Theory -- don't guy after the party most at fault, instead go after the party from whom you are most likely to obtain concessions/compensation/redress. In most geo-political conflicts, that part is usually the state, as contrasted with a guerrilla/terrorist group which operates outside the realm of any accountability.
I have a feeling that in the immediate aftermath of the attrocity in Russia there will be universal expressions in sympathy, but as time passes the expressions of sympathy will distort into some kind of attempt to blame the Russians for what happened. These would typically take the form of assertions on "incompetence" by security forces (ie. arbitrarily high standards of perfectionism, which nobody would be likely to meet), conspiracy theory accusations ("did authorities know in advance about these attacks? did they stage the events to discredit an enemy?"), etc.
As non-state actors grow increasingly lethal and brutal in their methods and capabilities, it may be legitimate to ask why they are not being given a higher level of scrutiny and held to a more critical standard by Human Rights organizations. The inability of HR groups to change their practices in the face of these changing realities will surely affect their credibility with the public.