You are confusing English usage with American usage. There are numerous differences - bonnet, instead of hood; boot, instead of trunk; lorry, instead of truck.
The Brits can use their terms correctly, even if YOU don’t like it — some of the muslims come from Bangladesh, etc.. not just Pakistan.
Incidentally, Brits use the term “Pakis” much more often than “Pakistanis”.
Not my late aunt, for sure!
ML/NJ