They are a part of Russia's electronic manufacturing infrastructure. Electronics like the one used in the missiles that fall on Ukrainian residential buildings, schools, hospitals, civilian power supplies, and so on. As such, the ethics is pretty clear - until Russia stops the terror campaign against Ukrainian civilians (at least), any company that is involved in enabling this campaign is ethically evil. It's not some complex conundrum - if a missile hits a residential high-rise, and you took part in making that missile, then you participated in that crime, even if indirectly.
> Should all russian companies shut down because of the war?
All that contribute to the war effort - yes, that would be a nice thing. Not really possible, practically, but nice. Realistically, probably only the most prominent get sanctioned, and they probably won't be shut down - just cut off from using Western resources.
> Would this be what we expect from all western companies, like when we attacked Iraq because of Weapons of Mass Destruction?
If Iraq wants to sanction all western companies, they are certainly free to do so. So far I don't think they had a slightest inclination to do it.