I can't, for the life of me, understand why Neil Wagner didn't play. I am not sure if Matt Henry was around but I would have picked him too over Patel. Henry also has an excellent record in county cricket and knows how to utilize English conditions, but he is not in the squad.
I get that Patel had a good tour of India, but this is England and a different story. If you're worried about Ben Stokes dismantling Patel, you don't trust him, and if you don't trust a spinner against anyone, you don't pick him. Especially when you have got a proven nuisance in Neil Wagner who at the very least will give you gut-bursting effort and constant attrition.