Hels, I find some of the threads on here pretty distasteful but I think you picked an interesting couple of examples.
In the case of the Muslim-bashing thread, the guy who started it probably wanted to drum up some support for his anti-Muslim views but almost no-one joined in and he ended up disowning the chain email he originally posted.
In the Israel/Palestine thread, I very much doubt that the guy posting the comments about Hitler is a BNP member - he seems to be trying to make a point (perhaps too subtly) that Hitler was seen as harmless and a potential ally by lots of world leaders until the extent of his activities became clear.
It's an internet forum, and all human life is here. There doesn't seem to be a dominant agenda, and even if individual threads can contain some views that are really objectionable there's generally someone on hand to present a differing one and correct any nonsense that's being spouted.