This by and large has been a great manga up till this final arc, even taking into account my complaints about stuff happening a bit too conveniently / unrealistically at times.
However, it feels like the author is refusing to wrestle with some really interesting philosophical conundrums he has set up, and instead is leaning on easy answers and contrivances. For example, this town situation where there are Johan's agents mixed with the towns people, and all are committing acts of violence, would be a great point where the complications (perhaps impossibility?) of deciphering "good guys" from "bad guys" could play out. Instead, the author has Lunge use his superhuman detective senses to immediately tell the difference.
Similarly, even if towns people and outsiders could be separated, it is pretty lazy to act as if being a towns person necessarily makes you an almost innocent, semi-unwilling participant, while being an outsider means you're evil.
Taking a step even further back, you also have the overall question of good vs evil morality, contrasted with the amorality that seems to be the message of Johan and his allies. The author seems to want to ignore the fact that their message is attractive because there is truth to it. This is looking like it may not get dealt with (hope I am wrong), and instead we get starry-eyed speeches like Grimmer's to Poppe about what human life should be like with all kinds of arbitrary moralizing.