he considers those casualties of war to get the stone, it's not necessarily part of his balancing the world
it's not like he went, "ok asgardians, your all going to be wiped just because i choose yall"
if another race had the stone, he'd wipe all of them too to get the stone
if the whole planet earth stood in his way to get to vision, he'd wipe the whole planet to get it no matter what
and he killed the dwarves so no one can stop him and his plan, again more of a casualty than just choosing them for balance
he isn't biased, whoever is in his way, he'll eliminate them if he had to but as you can see in the film he has no problem leaving his enemies alive once he gets what he wants