It's true that Russians didn't vote to attack Ukraine. Nevertheless, the invasion had broad popular support at the beginning.
According to whom?
You should understand that public opinion surveys in authoritarian countries are problematic. In autocracies, people might want to hide their opinions and give socially desirable answers that conform to the official government position for fear of facing repression or deviating from the consensus view.
According to my own relatives, friends, and acquaintances in Russia (where I'm from) – no one supports or ever supported in the beginning the total idiocracy which is happening.