Every time something like this comes up people freak out over the big bad successful brewery screwing over the 'little guy'. There's this whole protecting your patents and brand thing that goes over everyone's heads.
Except that isn't actually what's happening here.
See, as I sort-of alluded to in my other post, when someone is suing over a trademark violation, there usually has to be some sort of "lost profits" claim. Magic Hat must be able to claim that their profits have in some way been damaged by West Sixth's logo. They can't simply sue because someone else's logo looks vaguely similar.
Think of the "moron in a hurry" argument. Mountain Dew is unlikely to sue Magic Hat over their cucumber hibiscus logo, because a moron in a hurry wouldn't mistake cucumber hibiscus for mountain dew. One is a beer, and comes in bottles in the beer section of the store, and the other is a highly-recognizable soda that comes in bright green cans arranged in boxes. So despite the overt similarities in the logo design, Mountain Dew would have a losing argument in the courts, because they wouldn't be able to prove damages.
Furthermore, if Mountain Dew did try to sue Magic Hat, Magic Hat would fight back. It would be costly for both companies, and no one would win. On the other hand, if this case goes to court, West Sixth, being a small, young brewery, probably couldn't afford the legal fees. Therefore, even though Magic Hat almost certainly couldn't prove damages, that doesn't matter. Magic Hat is assuming that this won't go to court, because West Sixth is more likely to fold than to hire a decent lawyer.