That's unfortunate, and another reminder to stay with brands that have a reputation. Unfortunately almost all Ebikes were either assembled entirely in China or use Chinese made components if they are assembled elsewhere.
Almost all bike frames and components are made in China or Taiwan. The bias against their quality should be relative to the market they are trying to serve and the "price is king" mentality of many buyers. Also remember that the explosive growth markets like Eastern Europe, South America and other locations are where people can't afford cars or much else. The high demand for cheap bikes/transportation in those areas is often the catalyst for many of the inferior e-bike companies to get into the business. Most of these companies in China simply don't understand the U.S. market and they use the same "lowest price" and "flood the market" approach here that works elsewhere.
I'm starting a new e-bike company and quality is and has always been my biggest concern. In fact, I somewhat shared your opinion based on the bikes sold on Alibaba. Then I started looking deeper and after four months was able to locate and verify the quality of the assembly facility I use - they make all the bikes for Europe's version of the Sharper Image catalog. Then they flew to Interbike in Vegas to meet with me and had an engineer and account rep available to accompany me to every meeting with the major component manufacturers. The engineer checked specs and the rep worked the sales angles. It was awesome! In total, they have six full-time engineers with over 100 years of experience in designing bikes and e-bikes and integrating new technology. When I added Bafang bottom bracket torque sensors to all four of my bike models, engineers from Bafang met with "my" engineers in person over two days then returned to Bafang and made torque sensors specific to each e-bike. It delayed production by 6 weeks, but the quality of service and assembly is unmatched.
Yes there are some very cheap bikes made in China, but there are also some very good companies who are quality focused and test every component and battery used. I love my Chinese "partners," their passion for electric bikes, their pride in their craftsmanship, their willingness to pay more for better workers and their commitment to customers. Plus, they are just really good people. The type of positive energy people I like being around.
I'm sorry about the rant, but saying all e-bikes made in China or with Chinese parts are inferior is really unfair to those of us who do it the right way - and that is nearly every major brand of bike and e-bike out there.
I just think it's time to stop blaming the manufacturers and put the blame where it should be - on the re-sellers who put price and profit margin ahead of quality. For example, every one of my bikes was designed by my manufacturer to sell for $300 less than my cost, but I upgraded just about every component and part. Any brand can do that, some just don't want to spend that money even though they charge as if they did.
Just my two cents after pursuing this dream for over nine months and having many of my own misconceptions and myths shattered.