This, if you get to feeling badly, just remember:
1. The amount of children the Russians have killed - at least 400 (at thats probably sandbagging it a bit)
2. The number of civilians targeted and killed by the Russians
3. The amount of rapes and sexual assaults committed by Russians
4. The deliberately placed murderers and all sorts of mentally unstable in combat
5. The ecologic terrorism committed such as blowing up the dam
6. They've attempted to freeze and starve the elderly via attacks on infrastructure
7. They've destroyed over 3,000 school, hundreds of medical facilities, looted museums, stolen from farmers, mined fields
And the list goes on. All the while, remember the vast majority of the Russian population is cheering all this on and even happy they are doing it.
Did that one guy do it, maybe not? But did his death prevent anymore of this from happening, probably even if in some small regard (and potentially a large one).
If you bear all that in mind, you may find your sympathy eroding, and that's ok.