Sadly you will always get people who are sceptical of the "official" story just because it's the official story, just because he doesn't view Russia as unfavourably as most in this thread doesn't mean he's trolling (hence why I believe it's actually against forum rules to accuse him of such), there are plenty of other posters on this forum who "prefer to do my own research" with similarly skewed views on a variety of subjects
Because if everyone refused to engage with people who had different opinions/beliefs then the forum would turn into a Facebook style echo chamber, and that would suck.
I personally have no issue engaging with the pro-Russia posters because (A) over the course of this thread it has actually sometimes worked and (B) because I'm a firm believer that if your can't bare to have your own position questioned then that in itself is a question of your position, hence engagement.