As an American, I support Ukraine droning inside Russia. Fuck up their power plants, oil production, and bases! I believe most Americans would agree that in war, this tactic is fair game.
An eye for an eye makes the whole world blind. If Russia started using VX gas, would it be acceptable for Ukraine to start using Sarin? Absolutely fucking not. There is never a legitimate excuse for a war crime.
Civilian infrastructure can in fact a valid target if it assist the military. Electricity generation is used to maintain many military systems, including telecommunications, logistics, lighting, radar systems, and all sorts of manufacturing capability that assists the military.
So fucking what? Attacking civilian power infrastructure isn't the solution to fighting an enemy. Attack the military comms, logistics, lighting, radar, and manufacturing instead. Then everyone knows the attack is absolutely justified.