Not everyone lives in oceanside windows. Out of those who have looked at one they don't necessarily know that's an oil tanker; if it's through a beach, it's too distant (and likely heatwaved) to perceive something different with the deck at first sight, and at closer ranges I used to think they were just empty cargo ships "and of course the decks are so high up because the ship is floating higher up because it's lighter". Working with content who've never been on a ship they think there's nothing beneath the deck except what makes it float.

There's also the assumption that one wouldn't think "it's probably a different kind of oil tanker I haven't seen since it 'obviously' says gasoline". "What the fuck is an MMBtu?" Something related to gasoline, of course. Hindsight is not first sight.

Most US people are profoundly ignorant about energy infrastructure other than coal plants exist and the US relies on fossil fuels and you put petrol in your car. Just because you remember a great education doesn't mean others remember their bad education. Ask someone outside of the energy and environmental subject what they learned in Earth Science (sorry if I got the subject name wrong) other than the different types of rocks, tectonics, and what the weather really is.

it just means they have zero standing to complain

An infographic's purpose is to communicate to the uninitiated, not preach to the choir. This is just a single word that artificially limits its target audience and frankly I don't see why we're arguing so pointedly about it.

the reader would need to be willfully obtuse to construe the graphic to be about electric cars

I didn't think it was about cars either, but I still think it's plausible enough that one in a hundred could mistake it, and that is my point.

P.S.: Kudos for the diaeresis.