> Backspace makes sense if you see the computer as a fancy typewriter.
Backspace on a typewriter only moved the position (~cursor) back one space. Hence why its symbol is the same as the left arrow key's.
Backwards Delete was a separate additional key, if the typewriter even had one, and its symbol was a cross inside an outlined left-arrow: ⌫. Current Apple keyboard has this symbol on the "Backspace" key in some regions instead of the text "delete", but older ones did have the left arrow.
Apple calling it "Delete" goes back to Apple II. Many other older computer platforms also called it "Delete". DEC used the ⌫ symbol.
At least you don't have to type the same letters while holding a thin tape over your screen to erase them!
Apple also had separate Return and Enter symbols on keyboards for a while, which also sounds like typewriter territory but their intended use was a bit different: https://creativepro.com/a-tale-of-two-enter-keys/