1. They don't think about these kinds of second-order effects. They see that this company is somehow involved with the government and that's it. Their electorate won't care about these kinds of details because they're "doing something" to supposedly stop the war sooner.
2. They think that Russians would somehow revolt against the government. This doesn't work — the Russian government lacks any meaningful feedback mechanisms. By protesting, you'd expose yourself to immense personal risks for no discernible effect. Unless you're a heavily armed private army heading straight for Moscow.
I strongly disagree that these are the only 2 possible explanations. The first is clearly not true — these second order effects are well known and often discussed, and the fact that sanctions are used in circumstances when the population is not expected to revolt shows that the second one isn’t the only remaining reason to use sanctions.