IME, KL short-haul business class fares are not especially high compared to AF nor to many other European carriers like, e.g., LH, AZ, IB, etc...
BA and LX are a different kettle of fish. Both have followed a strategy of offering cheaper business class tickets to many destinations albeit with much more restrictive conditions. Both are trying to attract a premium leisure clientele into their C cabin, at least on certain routes, whereas airlines like KL, AF, LH, etc... are targetting pretty much the business market only with their C class fare range.