Anyone that commits a war crime should be held accountable.
Fortunately the Ukranian war crimes appear to be isolated incidents against Russian soldiers. Unfortunately it appears Russian soldiers are being given orders to commit war crimes.
Trying to defend Russias policy on unarmed civilians because there's evidence of Ukrainians executing Russian soldiers makes you look like an ass.
You are right, all those responsible for war crimes must be punished, regardless of the flag under which they commit them. But there is a nuance, the torture and murder of Russian prisoners of war are undeniable and documented, unlike Ukrainian fakes and provocations.