"Bad guys can't use it" is per definition incompatible with free software.
For this author's definition of "bad guys" (megacorps), AGPL is probably the easiest poison pill. As with all poison pills, this will also make many (most?) "good" users unable to use it.
This project is no curl or database engine, it seems to be a slightly easier way to set HTTP response headers. I bet most of the uses are transitive (someone using something that uses something that uses a framework that uses something that uses this project).
In particular, this project is something small enough that nobody will pay for it, not because it's not worth it, but because the friction of paying for it is higher than rewriting it from scratch. And "the bad guys" are unlikely to use it directly in their major products due to the pure nature of it.
In most cases, but especially this one IMO, you just get to choose wheter to contribute to the commons, the actual commons, for everyone, including "the bad guys" - or not.