And yes, fudding does work. Don't know the extent, but it does work in many cases. It gives some people doubt specially when the market is not too good. It can even work with Bitcoin, if the media decides to coordinate doubt. Whether the coin is shitty or not still doesn't mean that such low quality troll posting is right, which is the point of this thread. I mean lets say that the coin is shitty, should I be happy that these two have hijacked the thread with constant trolling and be like, "Oh chucks, it's ok because it's a shit coin."
FUD (whatever that is) is not against the forum rules as far as I know.
Trolling by definition only works if you get agitated by it. So yes, addressing those posts in a calm and factual manner is one way to deal with it. Another way would be to not feed the trolls and ignore them. Yet another option would be to report the posts to the moderator and hope for the best but I assume you've already tried this since you're now resorting to meta-complaints.
You're quite right that this thread is a waste if you think that only people who invested in the coin and/or have reasonable (as defined by you) concerns should be able to post in the coin's thread. You'll get no sympathy from me on this.