I've been through DTW Customs 20+ times in the last 8 years and have yet to go through any type of screening with them. I just hand them my form and walk out the door. They have all been European flights. Still waiting for one of these "horrific" experiences.
You're Lucky.
I've been through DTW Customs/Immigrations 20+ times in the same period and the norm is a secondary inspection with aggressive questioning. I've even had CBP officers pull the good cop / bad cop routine on me.
Doesn't matter if I'm coming in from Europe or Asia.
Have also entered DTW on flights where every passenger on the flight was sent to secondary US Customs -- even had it happen on back to back trips two weeks apart.
As much as I like the facilities at DTW, I avoid using DTW as a port of entry.
I've never had problems at any other US port of entry, and this includes: JFK, ATL, MEM, MSP, EWR, IAH, BOS, MIA, ORD, LAX, SFO, and HNL.