DRT, as I recall things, the first LE-only loads were the +P+ .38 Special and 9mm. The theory was that since powerful loads could accelerate wear, corporate counsel for the manufacturers didn't want them having liability for broken or blown up guns. Restricting these loads to LE, and requiring the purchasing agencies to sign liability waivers, made sense. There were lots of old .38s and some weak 9mms to worry about. There was some logic to it.
In the rounds you mention, however, the logic of the LE-only sales policy totally escapes me.
Wishing I could have made sense of it for both of us,