Weirdo types that decided they were in charge of naming things decided to name it Aluminium so it "matched" the likes of other metals like titanium, iridium, etc
Guy that named it called it Aluminum, Alumium, and Aluminium. Aluminium stuck, even in the US.
Then some weirdo types decided they were in charge of naming things in the US decided it needs to be Aluminum. It took them about 50-90 years to succeed.
No, the guy who discovered it called it Alumium, after Alum. Both Aluminum and Aluminium were later constructions by journals on opposite sides of the pond.
That's not how acronym pronunciation works though. We don't pronounce them based on the words they stand for, otherwise we would pronounce NASA, SCUBA, LASER, etc. differently. Both pronunciations have valid arguments so why can't we just accept both and stop being weird about it.