"they aren't blocking any of the rest of the river"
I bet they are. I don't have specifics, but if the objective is to keep the invaders out, they will line the Rio Grande with razor wire.
And they are using weapons against civvies, wherever they're using them. Ukrainians, Palestinians, Yemenis, most of the casualties are always civilians. It seems Europe is gearing up to replace Ukrainians who have been genocided beyond adequate supply of fighting age men. The US will have to back out of the European theater to focus on the ME, and Europe will have to die now that they've run out of Ukrainians.
Thanks!