Remember that you aren't forced to vote for my mission, it can be voted down to get a random card from the deck. That's not a good thing, as we've already established, but it's not quite as terrible as being forced to vote yes or instantly lose as in Resistance.
And right now, I don't find Arch's comment suspicious. Maybe there's something in it I'm missing, but it seemed rather tongue in cheek (heck it started with a vote for his suspicion, that seems like a pretty clear indicator to me), and well everything else that followed was just first post nonsense. But it got people talking and discussing suspicions, and honestly that's probably a good thing. I'm not saying I trust Arch either, just that I find it odd to jump on him based on what was effectively a RVS first post.
However something else I feel is worth pointing out is, I think that a lot like in Resistance, in this game it's more important to find one or two people that you trust, rather than aiming to scumhunt. Obviously, the latter is important, but unless you can nail Hitler, it's much more important to find one or two people you feel confident having as President and/or Chancellor. So rather than looking for who you are most suspicious of, it's better to look for who you think you can trust the most.