That is absolutely incorrect. The BCAPL rules say no such thing. Specifically, what they do say is in Rule 1-30-2:
"It is a foul if your cue tip is still in contact with the cue ball when the cue ball strikes an object ball. However, such a stroke may be considered legal if the object ball is legal and cue ball strikes it at a very fine angle." (Emphasis added.)
"May be." Not "assumes is legal"
Furthermore, BCAPL Applied Ruling 1-30 adds:
"...when attempting to avoid a foul by complying with the provisions of the rule, there is not necessarily a particular angle that will guarantee a legal shot in any given circumstance. Whether a shot of this type is legal is affected by several factors, and the referee's judgment is final."
Furthermore still, the BCAPL rules mirror WSR - AKA your "BCA" rules - almost exactly. This is from WSR 6.7:
"If the cue ball is very close to an object ball, and the shooter barely grazes that object ball on the shot, the shot is assumed not to violate the first paragraph of this rule, even though the tip is arguably still on the cue ball when ball-ball contact is made."
Your reference is incomplete and misleading. The BCAPL rules only allow for accidental movement of a single ball in such a situation. Also, per the BCAPL rules, if the referee judges that any such movement was intentional, it is specifically penalized as a deliberate foul.
The same situation is partially covered under WSR Regulation 20, but the rules
are potentially more forgiving than BCAPL rules, allowing for movement of multiple balls under Regulation 20, and not specifying any particular penalty for intentional movement.
Just in the "real world" of 60,000+ BCAPL players, and anyone else who wants a set of rules that closely mirrors WSR while providing drastically more guidance in hundreds of real world "what if" situations.
Buddy