I understand if the original posters in those threads seem optimistic that their ideas might work, and are the sort of thing that is needed to keep science reaching new areas of understanding instead of stagnating, in the spirit of Clarke et al.
Sometimes it takes an inspired idea to lead to the most brilliant discoveries, and at other times the idea is a very plausible solution to a real problem (hence the old saying "necessity is the mother of invention") and it is for this reason that I feel that such OPs of such threads are still being given the benefit of the doubt (and rightly so, otherwise this place would get dull very quickly).
Yet I get the impression that they feel they can carry their side of the argument solely by pointing out Mankind's need to push things forward instead of providing exact details of how and why to do it, without backing it up with scientific evidence or even their own working (and sometimes refusing to do so) to the point that their scientific method has more than a touch of blind faith about it. It's this stubbornness which clashes with the more rational thinking of others posting that causes a lot of the tensions in this forum.
That it seems to involve the same posters seems to have created a situation where the thread starter has developed a reputation which is being judged as opposed to the idea. On the one hand, there is an unfair air of persecution against the thread starter to the point of trolling, but on the other hand highlights the thread starter's need to get the better of their peers and to be proven right at whatever cost, even if it means reiterating their ideas to seemingly derail other people's threads.