Townies use plenty of bad logic, perhaps more than scum. There are plenty of illogical townies out there, but at least they're sincere in their naivete. Players who use poor or zero logic are nearly as likely to be town as scum. I see this as suggesting that Hayumi's posts, which you find unsettling, could stem from sincere townie logic that simply appears flawed or suspicious under scrutiny.
The real problem with justification is that people make stuff up all the time in Mafia. People who are better at justifying their actions do better against people looking for a strictly "logical" case, whether or not that person is scum. In my estimation, the current metagame reveals that Town are more likely as opposed to scum to make minor mistakes in justification. Hayumi struggling to justify their stance or posts about Sparkles, leading to what you perceive as suspicious posts, may fit this pattern of townies having difficulty articulating their reasoning under pressure (rather than indicating scum intent).
Your reaction, feeling that the posts are unsettling, aligns with Behavioral Scumhunting (BSHing). You can be reading casually and spot perceived insincerity. You then use logic to back it up. Once you've got a gut feeling about someone, you should be able to go back in the thread and build a case on it. Gut can be [unwittingly] founded in logic, and logic can be [unwittingly] founded on gut. Your gut feeling that something is off is prompting a logical examination, but this gut feeling itself can arise even when observing a fellow townie like Hayumi, whose communication style or logic clashes with your own.
Furthermore, townies are more sincere than scum because their goals are different. However, players sometimes post when hurried, tired, or otherwise not fully focused. Consequently, during the course of a game thread, it is not unusual for players to make statements that might contain phrasing that appears inconsistent or lacks typical clarity. This can happen to townies under pressure, like Hayumi appears to be, just as easily as it can happen to scum, explaining why interactions can seem unsettling even between town players.
Therefore, I see this interaction as stemming from common town dynamics: one player (Hayumi) potentially making logical justification errors typical of townies under pressure, and another player (you) reacting with a gut feeling (BSHing) that something is behaviorally off, leading to a logical challenge (LSHing or logical scumhunting)—a classic pattern I see as common in town-vs-town conflicts.
