There is more to the Behringer situation than just ethics. Quality is a factor too. My first exposure to Behringer was a little more than 20 years ago. At the time I was not into modular but I was into Hi-Fi. I purchased a fancy Behringer digital equalizer (19" rack mount) and straight out of the box it had an extremely annoying echo that would randomly come and go on the right channel, and the audio quality was not very good either. This EQ was supposed to use its included microphone to measure the room's response and adjust the EQ parameters accordingly--this did not work. As part of my troubleshooting process I tested the microphone by itself and found its response to be all over the place. I was able to operate the EQ manually but no matter what I did the sound quality problem and the right-channel echo persisted. Behringer's tech support was useless, luckily the dealer I bought it from was willing to take it back and give me a refund. The unit was cheaply built given the price and their customer service was essentially non-existant.
The next time I heard about Behringer was on a youtube channel focusing on vintage electronics. Things like 1950'-1980's computers, teletypes, electromechanical calculators, vintage electronic test equipment, early space communications gear, were the usual features on the channel. Then one day a modern Behringer UB1202 module shows up instead of the expected vintage NASA stuff. I didn't know what Eurorack was at the time, but I do rembember the engineer complaining as he replaced every capacitor in the module because they were bottom-of-the-barrel junk which had all failed.
On the ethics side of things, I feel their copying of other designs is reprehensible, but at the same time I think that kind of thing is tricky to talk about. I would much rather buy from innovators rather than soulless corporations mass-producing inferior copies of someone else's idea but the harsh reality is that we all have to do that kind of thing from time to time. I'd bet that many of those who would criticize others for purchasing Behringer modules out of financial necessity own plenty of products which were copied from other designs without credit, they're just things they don't notice or care about. Do you own a socket set? If it wasn't made by Snap-On, it's a knockoff....but I certainly can't fault the average person for buying a cheaper one. How many of us have Ikea furniture instead of buying handmade from small designers?