@Stosh, I see no where in the BSA docs that say any PDA is acceptable. They go to great lengths to say you cannot allow it in crews, so I would expect what's good for the goose...
It is not a matter of how positive it is. I have give you tons of examples of stuff that is positive for Scouts which BSA frowns upon or outright says don't do. The point is, if you allow it for some you have to allow it for all. You cannot say, "Mr & Mrs Stosh *can* show PDA but Mr. Brown and Miss. White cannot." That's just not right.
Great lengths? Each crew is to set their own PDA policy -- defining what is acceptable in their by-laws. It is certainly not mandated by national.
So, following your logic, since venturers are permitted to allow certain forms of PDA -- and even the crews with bans "on the books" tend to grant latitude to engaged/married couples among the ranks, we scouters are permitted to grant that same latitude to married couples.
I'm pretty sure that Stosh is not suggesting that in his troop, Mrs Q and I would be asked to behave more discretely than he and his wife. We would hold each other to some reasonable standard and move on. Maybe he'd warn me if this group of scouts were the kind to not let overhear one's spouse's pet name, and that would be it.
At the same time, I bet we'd pick up real quick that Flagg's outfit is more discrete, and we'd act accordingly.