I just came across a comment where someone was annoyed at having to
use American spellings when programming due to the fact that many
libraries use American spelling.
I can sympathise with not wanting to spell colour as
color, but I was less sympathetic when he complained about having
to use the spelling Globalization in C# libraries.
As I understand it, the use of the spellings -ise and
-isation are considered a UK thing, and are not used (or are less
common) in the US. Nevertheless, the converse is not true: that is, the
spellings -ize and -ization are not confined to the US, but
are in use in the UK as well. I'm not even sure whether the -s- spellings
have a majority in the UK.
Besides, if they want to use "proper" and "traditional" spellings
rather than "new-fangled" and "alternative" ones, then they should be
using -z- anyway; to the best of my knowledge, that morpheme comes from
Greek -ίζω via Latin -iz-, so the spelling with -z- is more justified
etymologically. (An exception is analyse, which had an -s- [well,
a sigma] in the original Ancient Greek; the spelling analyze is, I
suppose, by analogy with verbs in -ize.) For that matter, they
should also call the chemical element aluminum, which was its
official name; the spelling aluminium is a later modification.
As for me, I prefer the spellings colour, globalisation,
aluminium, but more because it's what I grew up with than because I
think that all those spellings are "more original" or "the only proper
British spelling".