"If we are unable to substantiate our thoughts we place the prefix "In my opinion""
No, whether one states the fact that GTGP is a scam, or the frankly ridiculous opinion that in spite of all the evidence to the contrary, GTGP is a legitimate stock with an honest CEO, iHub ToU make it clear no such disclaimer is necessary:
"It is understood that all posts on the site are to be considered opinions. They do not need to indicate this in their posts."