It is, after all, what the article calls it: Lethal force. The two deepest lessons I was taught about firearms were these:

1) Never point a gun at anything you're not going to shoot and

2) Never shoot anything you don't intend to kill.

Sure, there are situations where disabling a target may be sufficient, but it's often unclear until too late whether a given situation is one such. But more to the point, "aim to disable (???)" presumes two absurd things, that ones marksmanship is consistently perfect under all conditions, and that an accurately aimed nonlethal shot will completely incapacitate the target. I'm not sure which is the more foolish notion.

As to Russias realpolitik here, as noted, it's hard to say. Maybe they don't want the long term headache reasserting control would be, but their comment about UN authorization seems more telling to me: Rather than relying on a Kyrgyzstan invitation to legitimize what would likely end in reabsorbtion into Russia they're waiting for a greenlight from an international community that would thus have removed much of its freedom to respond should Russia simply seize the country outright. At worst the UN and its members would be forced into the unappealing implication they were wrong to authorize Russian action to begin, but at best they'd be neutralized by that bit of politics and Russias ability to say, "hey, it was YOUR idea; why are you complaining?" Once an international consensus is reached that Russia should intervene, it will be very hard to later reach another consensus saying they went too far.