So I think I fully understand you now.
I guess I'm still struggling to accept this is the rule, for the following reasons:
• Onepocket.org says: "6.3 Cue ball after a foul: Following either a pocket scratch or the cue ball jumping the table, the incoming player has cue ball in hand. Following any other standard foul, the cue ball is played where it lies."
So, WSR applies for items not covered by their rules. But I'd argue this sitution is covered by their rules - there's only 2 conditions for ball in hand. My shot is not one of them.
• The vast majority of people I've talked to, like 90%, don't play this way, including some longtime 1-pocket players. But I can concede that maybe there's a whole world of pros and high-stakes gamblers who always go by this rule, and I'm just unaware because I'm not in that world.
Also, the rule you quoted seems concerned with hitting an invalid ball, I dunno if this is one you personally wrote but I assume the point of it is to prevent players from shooting backwards in games like 14.1 and 8-ball. I'd argue that if you or the other BCA/WPA rule authors didn't have one pocket in mind, and never mention it (while all the other common games do get mentioned)... maybe it shouldn't apply?