Same reason as the other providers removed in the past - they contacted me and asked for its removal.
Unfortunately, I predicted that would happen. Technically, you reverse-engineered their product to get the functionality and that's clearly against EULA/ToS, not just of Bitdefender, but any other software in general.
Not a smart move by B or other vendors who asked to remove their API.
B, for example, provides some sort of web protection free of charge through TrafficLight as a promotional service for their paid products; Osprey can serve the same job, even in a better way by less slowing down of web browsing.
The problem is
@Foulest reverse-engineered their product without their approval and this goes against their EULA/ToS he agreed to while using their extension. They warned him and if he didn't comply, they could start a lawsuit to protect their own rights and
@Foulest couldn't possibly win that case.
And yes, Bitdefender offers Traffic Light for free and as you yourself mentioned, its goal is to get you to buy their premium product(s). When used through Osprey, Bitdefender almost doesn't get any visibility, and none of their other products are mentioned. Then, there's data argument too. I have no doubt Traffic Light extension collects much more data than what Osprey would send them.
There are tiny chances they would allow him to use their service in extension if he asked, but I doubt in that.
Personally, I have disabled the AdGuardDNS filter. Since this is a company from the Russian Federation that has moved offshore to Cyprus, I don't want to jeopardize my personal data or just help this company collect data. You can do this at your discretion, of course.
No need. AdGuard are one of the good guys that originally came from Russia. From what I saw, they exited Russia completely and moved to Cyprus. They even offered to relocate their employees as devs working for AdGuard are from both, Ukraine and Russia. They are also one of the handful companies that spoke against the aggression as well. Totally safe to use!
See this:
Official response from AdGuard to SetApp allegations.