This mod overwrites the Electric Furnaces mod version of the electric steel furnace. I think it's by having an identical name. This is gameplay relevant because the other mod makes them speed 2, while this mod overwrites them to speed 1, making them identical performance to Electric Furnaces' electric stone furnace. I was able to fix it by just deleting all mentions of the furnace in this mod, but I'm not sure what you want to do here balance-wise if the player has the other mod installed.

So in other words, it is incompatible with another mod because it literally does the same?

There is not exactly anything for me to do here besides mark the mod you mentioned as incompatible, so you can't launch them at the same time.