Ok, having reread all of BoomFrog's posts:
I don't think the statement towards plytho is alignment indicative. That early on in the game, I'd be assuming that people are town until their behaviour shows otherwise, and I don't think BoomFrog is immune to jumping to grandiose conclusions from pretty little evidence.
I do think his position towards Sash claiming is interesting. On page 2, he tells Mark that it's good to determine where the Sash is to prevent PRs from getting blocked. Then, on page 4, he states that he's against the claims because he says he's realised that doctors or watchers could be blocked and the NK could safely target the Sash. Then plytho points out an issue with how he's interpreting the wording, and he switches back his position. I think he's coming from a townie place here, he's actually trying to check the mechanics of the Sash claim to see if there's any problems, unlike a lot of people.
His joky buddying with Zen comes off as a bit weird. On that note, he's gone for a lot of explicit jokes this game. Apparently that was the gambit? He says later that he was being more flippant than usual.
He correctly concludes that it's not worth focusing on a Sash victory as Town D1, unlike some people
Once he starts being put under some suspicion, he steps up his activity, which is slightly scummy (I'd expect Town!BoomFrog to be more consistently active), but presents some pretty good reasoning against plytho and Jimbob.
I think his defence against the BoomFrog and plytho situation makes a lot of sense, going with my initial impression of the situation.
Throughout, he's been doing plenty of probing questions and explaining his reads.
Overall, not seeing the scummy behaviour from him. I think people are reading way, way too much into him calling plytho a jerk, and most of everything else has been townie.