If they were being treated as violent criminals, there would be a passage in there about how they were thrown to the ground, a knee placed on their back, were cuffed behind the back, and held down until the matter was resolved. If that had happened, I think the poster would have chosen to excerpt those parts of the article.
It sounds to me like a lot of discretion was used here, and this family was treated a lot better than somebody would have been if they looked more like your typical violent criminal. But discretion only goes so far. If you are on a military base in what is presumed to be a stolen vehicle, you can expect to be handcuffed.
It bothers me that they were looking at all the cars in the lot. Observers are going to report such activity in this era of high security. Stupid thing to do.
Heck if they were in LA they woulda been shot at about 79 times.