Probably because they act inhumanely?

The rape and torture of combatants and civilians? The bombing of critical infrastructure to leave a scorched earth on retreat? The indiscriminate targeting of civilian evacuees? The theft of Ukranian children and taking them to Russia to brainwash them at best and put them into the sex trade as one of the worse options? The attempts and calls for genocide against another group of people?

Humans have a social contract that is more or less consistent across the globe. We are social animals endowed with empathy and we don't enjoy seeing others suffering. If you break this social contract, why would you be surprised that people treat you as though you were inhuman? Why are you bothering to turn this plight onto the Russians who are not currently being targeted by any of the above?

Friendly reminder that this method of turning the Russians into the victims of "russophobia" in any thread about Ukraine or Russias policies is russian troll posting 101. You should consider hard who you are currently coming to the defense of.