Yes, your article is entertaining and not solely because I was born in England but because I have lived for. the last 50+ years in Australia - a place which has a confused amalgam of British, North American and local variants of almost any word of over two syllables and many of less.
However, to answer your title question - "They don't." The reality is that either is acceptable and that both have been used by both the British and their colonial offshoots, the North Americans.
Hardy, in fact, originally named the compound alumium.
A characteristic of the English language is that it borrows from many other languages and appears to have always done so.
When new substances are discovered, their composition may not be clearly understood or a name may not already exist. It has long been the convention that the discoverer of new substance has the right to name it.
However, only in relatively modern times, i.e. since the early 20th Century, has there come about the formation of bodies to standardise or 'prescribe' appropriate naming conventions. These have generally evolved from prior usage and/or the use of Latin or Greek word roots and appropriate suffixes usually derived from ideas of why or how the substance came to be.
Although there was at least one individual who felt it more appropriate to favour a 'classical' or, in the sense that you allude to it, pretentious naming, the actual result of the two current versions of the name are more accidental than intentional. Indeed, for a significant time, the British variant, 'aluminium' was dominant in North America also.
There are many anomalies in scientific nomenclature, not least brought about by inconsistency and existence of precedents in usage, some appropriate and others less so.
My own view is that this provides one more reason that language is so fascinating, stimulating and fun. The apparent need of North Americans to baulk at conventional English usage is probably a result of inherited prejudice or enmity having arisen because of the Revolution. The option for eradicating letters thus making many words easier to pronounce is probably similarly caused, though it may just be that it is laziness or an early adoption of the tendency to slang, abbreviation, stilted, texting type use of language that has become so pervasive today.
It is a case that humanity generally seems to be dumbing down. Whether the ever poorer use of and understanding of language and loss of nuance in its use is a cause or a result of that, I'm not sure. I simply regret it.
