That being the case, why did the wealthy Jewish people wear purple clothing?
Answer Pete… You ask a marvelous question! The answer varies according to tradition, but I’ll give you my 2 cents worth. There is a commandment not to touch the carcasses of forbidden (unclean) animals. There is no such commandment however concerning the live animal. I can touch pig but not pork. Additionally, some animal secretions (ie honey) are kosher even though the animal themselves is not. Orthodox Judaism maintains that the dye used in making one of the fringes for our tallis (prayer shawl) came exclusively from said critter. There are, however, numerous other sources, including vegetable matter. There is a movement within Judaism today to return to blue fringes, but using these other ‘kosher’ dyes. The dolphin skins used atop the Mishkan (Tent of Meeting) probably also came from a non-kosher source (swimming mammals do not generally have cloven hooves and chew their cud). However, there are several examples of a specific commandment from G-d superceeding a general commandment
