one thinks maybe BA is better off not having such a customer
Clearly BA thinks so too - but it is commercially nonsensical (assuming Profot is giving us a fair account of the situation). Tossing away a big-paying J-class passenger, especially in the current business travel climate, is sheer unbridled lunacy. As has been noted, other airlines allow changes for genuine compassionate reasons - there may be hoops to jumps through (medical certificates, etc), but they do it - and even for ordinary Y class passengers.
Profot will be snapped up by CX (you can use your points on them, much better than QF in my experience), SQ, EK and others plying the Kangaroo Route. BA can ponder their empty Club World cabins, plummeting revenue, and wonder why.
And this is only one of several recent threads about BA customer relations decisions that defy any rational commercial explanation. What is going on?