The rationale they provide is that you can't see the door to the bus. So we are looking at the driver's side of the bus. Ignore "Which was is the bus going?" and instead ask "Which side is the front of the bus?"

And, knowing that we are looking at the driver's side because of the absence of doors, the answer depends on which side of the road the bus is designed to be driven on.

Oh is that supposed to be the rationale?

I mean I can't even tell. Because no bus looks the way the bus in the image looks.

I've never in my life seen a bus where the windshield was the same size and shape as the back window. Never in my life seen a bus that didn't have brake lights or turn signals. And so forth.

In other words, there are so many things wrong with the "bus" that I don't know why you'd assume that if the "artist" had drawn it from the other side they would have bothered to include a door.

I think you've just confirmed the post's point about overanalysis. This type of thinking is exactly why adults get it right less often than children.

Kids immediately recognize the view must be from the driver's side of the bus because they're not examining the situation. They're taking the first piece of relevant information and rolling with it. No door means passengers get on the other side, so it's going whatever way you assume traffic across the street should go based on where you live.

But there is a difference in the picture. You'd also determine that it's going left when looking at the windshields, as only the left side is completely straight.

Honestly, this image is a terrible example to illustrate their point. I think it's more likely that children are more likely to actually use public transit, which is why they'd be able to detect the missing door quickly.

The right windshield is straight as well, you see part of a building behind it

I meant the small indention below the windshield that's only on the right side. The black line from the window ends slightly further out then the chassis of the bus

Indeed, my assumption was that this was some simplified drawing of a bus that didn't have doors in the first place

The bus is missing many details of a real bus, so it's clearly an abstraction that leaves out detail, meaning that it's reasonable to assume the artist may have crudely left out doors from the picture. This doesn't make the kids "right".