There's the government, and there's the people. These are very separate entities. You can't combine them like that.
You're effectively punishing Russian people for something they have no say in. There is no public opinion in this country and the government lacks any meaningful feedback mechanisms.
Sanctions largely punish the people, not the government, and we implement them anyways.
There's ways to feedback, even if they aren't petitioning the government for redress of grievances. The US infamously has a saying about four boxes of liberty: "Soap box, ballot box, jury box, ..." Given the first three are non-functional, there remains the fourth.
No, trust me, it's an autocracy and there are no feedback mechanisms left. They were steadily dismantled over the years, and now something as innocent as calling for peace in a public place would get you arrested, instantly. Latest addition is a law that gets you 15 years in prison for "critiquing the use of Russian armed forces". And another one, also prison time, for "spreading fake information" about them, where fake is anything that doesn't come from the government itself. I wish I was making this up.
And the highest level in the government where there are people that were fairly elected is the municipal deputies in large cities, like Moscow and St Petersburg. They manage municipal districts, which are the smallest administrative subdivisions of these cities. Anything higher is kind of a sealed system, you can never get in there, and the only way out is to die, it seems.
edit: I googled that phrase. No, not really possible either. He's surrounded by either loyalists or "I get paid so I don't care" kind of people, and it would take the balls the size of the earth to do this. It's been discussed many, many times. I remember watching a video that detailed why an assassination would be extremely unlikely but I can't find it now.
