Tripadvisor.com forums consist of volunteers from the online public. Therefore, one will find an array of characters and personalities. Some are scammers pushing their wares. Others (the majority) are fellow travelers. However, there are some specific forums (e.g. Paris) that consist of regulars (some residents of that particular city/country) and they can be absolutely rude and nasty. What is very frustrating and galling is when people get their posts deleted arbitrarily by other forum members. That's legitimate if the posts were indeed inflammatory or 'inappropriate' (Tripadvisor's term). But what's happening more and more nowadays is that some of these forum posters, who have a personal dislike towards other forum posters, report innocent posts as being 'inappropriate'. There is no way to prove that is happening other than what you witness yourself. Don't even bother arguing your point with the Tripadvisor personnel as they could care less.
In short, Tripadvisor may be a good way to learn about traveling. But you need to keep in mind that there are quite very nasty, negative types who are there day and night hoping to make things difficult for others.