It seems that people often confuse -ian and -itan.
-ian would be like an identifier for e.g. an occupation or a state of being of a peron, “librarian” & “sectarian”.
-itan would define a person’s location or geographic affiliation: “metropolitan”, “cosmopolitan”.

In this case, JavaPolis would have mixed up semantics.
A quick search for “metropolian” revealed that English speakers seem to ignore this rule.

French ending is “Metropolitain” (etymology give “metropolitanus” for latin).

So…people just don’t know their grammar, it seems? But hey…they did a good coding job on the site. Compensates. Haha. 😉