A bit of BS or arrogance.... paying a premium fare does make a premium passenger. Collecting miles in a FFP makes a status passenger. Two different things.

BA has chosen to limit seat selection to status passengers and those paying full premium fares. Their choice, but annoying for those that fly BA infrequently or collect in another FFP. And as far as I know one of the few airlines that doesn't allow advanced seat reservations for all traveling in Business, some do block a few preferred seats for status passengers but the rest is open to all.