I'm pretty sure the average liberal thinks this was supposed to be an election between Navalny and Putin. That's how misinformed they are.
You're also right. Putin is massively popular in Russia at a level libs can't seem to comprehend. The only major opposition he has involve the communists, but they mostly align with Putin's foreign policy anyway. Most polls show Putin with a 85% approval rating and libs will always think numbers like that are unfair or fabricated.