They're also funded by the National Endowment for Democracy who is funded by the US government. They also just happen to write articles that push US imperialism encouraging war and overthrowing governments.
No, this is absolutely not. By the same logic everybody who worked before in the government would make their new employer "affiliated", but this is not what does this word mean. E.g. let's say, a security firm founded by former cops guards shopping malls: does it mean, this firm is affiliated with the police or it's just the best application of their skills?
The real evidence would be a proof that the agenda of Bellingcat is set by CIA. Not funding or other resources, not information or any other support, but the agenda. Not "roughly coincides", not "they work on the same targets", but "set by".
This is no more than one the many plausible explanations of their success, unsupported by real evidence.
>their articles should be treated with extreme skepticism
Do you mean facts or narratives? On the former, Bellingcat seems to be doing a good job.