Sure they are. There's a number of projects out there with a massive caveat on the front page that says "Not for production use". They are then more than free to close issues with comments like "Hey I'm researching a new refcell implementation, thanks for finding this, but I'm more interested in speed than safety at this point."
Actix did not put up a disclaimer, and in a lot of cases, either closed issues/patches without comment, or with a somewhat demeaning comment. It was not just published as a fast and safe production ready web framework, it was promoted as such, so the author should expect patches in that vein.
There were multiple bad actors involved here, but it stems from a maintainer who took issue with anyone finding problems in his code.