You're getting to caught up in this. The Aircraft will fly at Flaps 1 right up to Alpha Prot. The slower below S-speed, the less protection you have.
The FMGC displays S as the speed with config flaps 1 to give you a limit protection speed. You can go below it, right up to Alpha Prot, but you give up a lot of safety doing that. Not a big thing to go S minus 5 kts at config flaps 1, but why do it, what do you gain from that? Lot of variables there to consider, but balance them with the protection the FMGC is trying to provide you.
As for the pic TURNING BLUE, who's in charge there. You'll get your turn some day, respect the wishes of the guy or gal in the left seat(as well as the FMGC) and play it safe. Few knots isn't a big thing here. It's the concept of what you are trying to accomplish here.,