Sainsbury's is permitting Muslim checkout operators to refuse to handle customers' alcohol purchases on religious grounds. It means other members of staff have to be called over to scan in wine and beer for them at the till.And next is? Vegetarian employees not having to handle sales of meat products? Pacifist staff not having to deal with war games or toy guns? Green checkout operators only having to process sales of locally produced foods?
But stick with it for a moment in order to get a further angle on this. We are to assume that having to handle alcohol purchases is deeply offensive to some fundamental moral principle of the staff concerned. If you have trouble with putting yourself in their shoes, then substitute something else, something that would be deeply offensive to your own principles. You're working for a well-known supermarket chain, and find that they're selling human flesh as veal. You don't wish to be implicated by handling the sale. Or, if that's too far-fetched, then try this instead: you're having to sell products being produced by the super-exploitation of overworked and under-age labourers, that is, young children.
And all you do is to ask to be excused from handling such goods. You cooperate in an arrangement that gets the goods sold, calling over other staff to do the business, and you continue to work for the outfit that is selling these things.
Perhaps not so fundamental a moral principle after all.