It really seems to me, and I honestly have no evidence to support this other than the eye test and looking at our own hitters hot and cold zones... the Rays pitch to the hitter's weaknesses very effectively and really don't deviate from that plan. If the cold zone is away, they throw everything away, away, away, and take their chances that the hitters won't suddenly get good at hitting in their weakest areas. Yeah, they'll be the odd mistake pitch and missed locations, but they don't change unless the hitter's show them they have to.
If I were a betting man, I would put a decent amount of money on the Rays having a very good pitch analytics department that digs way deeper than other orgs into pitch sequencing, locations, hot/cold zones in combination with sequencing etc. It would really help explain why it seems like all the nobodies in the world can go there and pitch like they are a front of the rotation starter or top end pen arm.