The point is that this is a bulletinboard in which people express their own opinions.
When an individual person expresses their opinion by using plural personal pronouns, it gives the impression that they're speaking on behalf of a group of people.
On the other hand, a person who habitually expresses their own individual opinion by use of plural personal pronouns...well, there's a lot of things that can indicate. Look it up.
In short, when I post, I try to speak for myself, not others.