I cannot help feeling that the eating of "unclean" pork is related to the fact that the meat goes "off" so quickly in hot climates and is subsequently classed as unclean.
I'm sure that many of you (particularly from the UK) have heard of the saying "Never eat pork when there is no R in the month".
(May, June, July & August) when it is often very hot in the UK (well, most years anyway)
This of course was before the invention and widespread use of
refrigerators.