I have no problem with modulars or mobile homes. Just that you need to pay attention to what you purchase. Like you said some are trash. And they are sold as meeting code around here when they dont meet local code. They meet code in a different state where they were built.
That said I think people should have a choice as to what they buy be it site built or not. If it is a piece of crap be aware that you will need repairs sooner. And some of these are just crap. But I have also seen site built homes that were crap as well. I mentioned it above in reference to Mississippi.
***And some of these are just crap.***
I could show you a small town full of abandoned trailers. They do look like crap.
On the other hand, we had a home builder who built real shoddy stick built houses. His favorite way of shafting people was to buy an old termite ridden single story abandoned house, pull it to a new foundation, put nice siding on it, blow a little insulation in the attic, and I DO mean a Little, then pass it off to new buyers as a NEW HOME!