What's worse than those cheapo Amazon Chinese amp? Your dealer!
There are many angles to analyze the situation.
1. You went to a dealer which doesn't stock good Chinese amps and ask about it. Many audio dealer these days aren't any better than used car salemen. To put an analogy, you don't walk into a Ford dealer and ask them how good Honda's are. You won't expect them to tell you go to the Honda dealer nextdoor. They will of course tell you their cars/amps are better, that's their job!
2. Chinese amps comes in a whole spectrum of quality. There are the $400 300B tube amp from Amazon, and there are the good quality, Line Magnetic, Cayin, Willsenton, Prima Luna. I have a couple of LM amps and they sound great if matched with the correct speakers. If you look inside, the build quality is also top notched. Surely there are crap ones, but you just need to weed them out and don't generalize. Generalizing from solely looking at the poorest quality product is very commonplace these days, and it means that you will miss out on the better products.