Oh, I’m intimately aware. Just pointing my out that what most people call a steam “engine”… maybe only 10% of that is the actual engine. In something like a car especially. The actual engine is just a double acting cylinder and a few slide valves.
I think the negative response to this type of post is because you can take any field and do a reductive statement "It's Just XYZ". There is a hundred years of steam engine design "It's Just some valves".
It's just a way to either minimize someone's field, or way to show you only have a cursory understanding. Rarely does someone have a deep knowledge of a field and then also frame an overview of the field as "Just some bits".
Nuclear Physics is Just smashing atoms.
Biology is Just some Cells. Or Just looking through a microscope.
Computer Science is Just the application of And/OR statements. Or Just Boolean logic.
Internal Combustion Engines are just little explosion's in a cylinder.
F1 Cars are just an engine + battery + some wings.
Edit:
Honestly. I'm guilty of doing this too. I've "Just Learned" how people take it so have learned to adapt phrasing things that don't insult people.