Turban wearers was not meant in a detrimental manner as there are so many different indian type employees there that it was less controversial to group them as such. It shouldnt upset them or anybody else.
My brother works at Heathrow with a large number of turban wearers and that is what they told him they do. He also said he has been to parties and the curry is totally different to what he is used to from the local takeaway in Bedfont