This pronunciation thing does seem to be a class signifier. Upper class uberposhos will deliberately mispronounce, middlers and aspirationals will bump for what they believe is authenticity and a make a big fuss of doing so and reminding others that they're doing it wrong. Those the at the bottom don't care, they're on their fifteenth pint of San Miguel in Ma-lager.
If we're speaking English then, as far I care, we should use the anglicized pronunciation rather than mangling foreign pronunciation with comedy lisps and the like. Quite often it just sounds affected. That said, I was in a shop the other day and someone was asking for jalapeños with a j. Honestly, I was almost ready to correct him my best mildly racist comedy Speedy Gonzales accent.