"Perhaps" can be used to indicate true uncertainty, but often it's just a kind of weasel-wording used to avoid accountability for one's own words. How do you tell the difference? One way is to look at whether succeeding statements which build on the "perhaps" continue the uncertainty. Are phrases like "in that case" or "would be" present, or are such follow-ons stated with certainty? Perhaps the commenter was making a truly conditional statement. Perhaps s/he is just a cowardly asshole. Oh look, I said "perhaps" so we're all OK, right? Sorry, doesn't work that way. Sometimes deniability isn't so plausible after all. When you consider that same person's next comment, I think the reality of that "perhaps" is pretty apparent.