This is definitely not fringe conspiracy theorists. In fact I would argue that it's largely people familiar with the sport that are skeptical.
It was the same during the Amstrong times. I was racing as an amateur during those years, and lots of people were quite open about doping, i.e. everyone new someone who had been on training camp with people who were using, people asked others what they used... This particularly known for the top amateurs and continental pros. If you brought this up with regular cycling fans (particularly in the english speaking sphere), you would get accused of being a conspiracy theorist, that the top talent would not need to do this (only the talentless masses who could not make it otherwise...). Which is such a weird argument considering the gains we knew about. Well we know how history turned out.
Considering that it's the same people running the show (I encourage anyone to look into the history of Mauro Gianetti who believes that UAE would not do everything for a win), I believe everything we hear about is just the tip of the iceberg and reality is much worse. Cycling lost their right to benefit of the doubt a long time ago. As a side note, I don't believe they will every catch a high profile rider with those motor tests. Nobody actually wants to catch them, just imagine they find Pogacar was using a motor, that would be the death of cycling as a marketable sport. That would be swept under the carpet, just like Amstrongs positive EPO test was initially.