yes, ADE, i agree that this was a demonstration of a slapdown for other would-be defectors from the Russian sphere, or “roof” as they say over there.
They want to hurt Georgia, not necessarily take it over, supercargo. which brings us to your other points — I understand that there are competing narratives here, the one competing to the “ethnic cleansing” you put forward is that the Ossetian thugs, with Russian sponsorship fired at Georgian villages from within Tskhenvali, a tactic of (own) human shield much practiced by the so-called Palestinians (Hamas) and Hezbollah.
Georgians were presumably less restrained in their response than Israel has been (which restrained has not improved Israeli security).
With such competing narratives evidence is the only key, although I am sure Russians will come up with plenty victims. Evidence of Russian preparation all the way back to explicitly bringing it up at Kosovo discussions as eye-for-eye lends credence to Russia being the aggressor here.