Different opinions come from different experiences. For instance a gunsmith who has work on a lot of rifles will be influenced by the quality he sees and how often certain brands turn up with a problem, he will also be influenced by how safe he feels the material and designs are. The competition shooter [serious ones] are going to be influenced by how well a particular gun can be made to shoot. Every one has a right to an opinion and his own likes and dislikes.
An other thing some of us have been on here quit a while and the only person I know of who was compensated for having a certain opinion announced himself when he joined and rarely says anything, the rest of us just have an opinion usually due to a lot of experimenting.
I think some people are over defensive, and that makes me wonder about them, the last guy that made a lasting impression on me that was that way collected money for a charitable cause then disappeared.