It would be a bit of a dishonest question in my opinion. Take the oil and car industry in the US for example. They've spent the past 70 years or so dismantling alternative transport infrastructure (among other things...). So how are we now going to assign the blame to the guy driving his car to work, instead of taking the bus that takes 4x as long, requires 3 transfers, and has people openly taking drugs on it? In the ideal world, sure, there would be a fair and even playing field of alternatives and the blame would 100% lie with the consumers who choose from this totally even field of possibilities. But we don't live in that ideal world.

What if the guy in the car voted for pro-oil politicians whose campaign explicitly included expanding fossil fuel consumption and cutting budgets to trains and other public transit?

Because ultimately the way we organize society is we have a democracy and we vote on representatives to make the laws. Companies actually don't get to directly cut public transit, they have to convince voters to do that.