Are Ukraine not allowed to attack Russian positions now?
You've misconstrued my point. Whether we feel Ukraine can legitimately attack Russian territory or not is irrelevant. For clarity, I've no moral issue with it at all.
The issue is how Russia could construe such an attack; you can see it already: non-
military (quasi-military really) target hit; heartland of Russia; terrorism.
So the point is how Russia respond to such an attack, if it is one or they attempted to portray it as one. Let's not forget what Russia have said repeatedly...
And the fourth case is when an act of aggression is committed against Russia and its allies, which jeopardised the existence of the country itself, even without the use of nuclear weapons, that is, with the use of conventional weapons
That's their proclaimed right to use nuclear weapons, which they have mentioned several times. Russia do not take kindly to attacks on their soil.
Therefore, my point is not to criticise any such attack (if it is one), but rather suggest potential repercussions when you consider previous response to attacks.
Maybe. Who knows? If it is an attack by the Ukrainians or someone supporting their cause / not supporting the war, it's ballsy to say the least.
I have doubts about the false flag parts however because A) there's more convenient / softer targets that'll do the job and B) it'll be seen as a faux pas.
An attack close to Moscow by those pesky Ukrainians? It doesn't portray them very well if you get my gist. Why not blow up a hospital near the border etc?