You don't need to hide your intentions, they are obvious. It's the same as Nintendo fans making threads about the Vita, the gaming community sometimes makes me sick.
This is correct. Fans of X console will criticize Y console when it's doing bad, and vice-versa. It's an inevitable phenomenon that will exist forever as long as competiting consoles exist. Also, technically, these threads are legit comparisons which break no rules.
Considering the inevitability and legitimacy of these threads, there really is no point in complaining. Unless of course you can objectively demonstrate fallacious logic or rule-breaking behavior. Otherwise you just sound like a bitter fan proving that you are upset with these threads, which is more harmful than helpful; it discourages meaningful, serious discussion (which should be preferred over an explicit doom thread). And if the thread is truly bait, then you help to accomplish its goal.
Granted, most of the people who make these threads probably also act on emotions; but they at least present legit data. When confronted with threads like this, there are two suitable responses. (A) Ignore the thread altogether, or (B) Turn the thread into a meaningful serious discussion - doing may actually expose flaws within the OP rendering it ineffective at spreading doom. And if not, it at least creates a serious theme for the thread, preventing the childish, shallow "LOL DOOM" responses.