Millions of people travel to and within the US every year without incident, what gets reported is the admittedly terrible sounding times when that's not the case. Chances are very good that you'd have no problems.
I appreciate that the the chances of it happening to me are slim, but I'd be worried sick about it, and would find it hard to maintain my composure if it did happen.
(Aside: I'm 10 miles away from the largest NSA base outside the US and the local pubs are full of spooks, so arguably the US has come to me!)
I mean wen we get to the US, we have our flight ticket info sent prior, we have to add more data because it's the US, the ESTA, last time I got harassed in Paris by the American Airline because I need to know the address I'm going to (I told her to check my file, I don't remember it), how long I knew my girlfriend and stuff, the NSA knows everything about me (I'm not an US citizen), the TSA checked me, the border police checked me out of the country. When I arrive in front of the CBP agent, my privacy had already been thoroughly shredded in the name of security, and my personal data including credit card is gone in the wild without any recourse or oversight, there is absolutely no need to physically harass people at the border.
it is a win for both the US and travelers when this process goes smoothly.
The only stories that tend to get written are the extraordinary ones. Unfortunately, it's unlikely that a border official is going to have the opportunity to do something "extraordinary" for someone unless he saves a life with the Heimlich or something like that.
So the "I HAD A HORRIBLE TIME AT THE BORDER!" are the ones that tend to get written up and passed around. No one writes up the hundreds of millions of routine, boring border crossings.
(I find the lack of understanding this concept to be a source of lots of dumb discussions both on-line and off-line)