Uncle Dave nails it very succinctly there. Yes, you are entitled to your opinion, even if it's a rather wacky one. Yes, you are entitled to express that opinion out loud, though personally I'd draw the line at speech intended to spread hate or fear. If you're trying to influence or persuade other people to fall behind you, though, you'd better be ready to be challenged to support your opinion, to demonstrate that you are not prejudiced, bigoted or otherwise unduly partial. Even if you're not challenged, you should be honest enough to offer that support in any case. That would mark you out as a person of integrity, not a mere charlatan. What we often see in discussions here are opinions expressed that are either unsupported or wrong-headedly supported. An anti-evolution opinion that describes evolutionary biologists as operating from a faith position or following some sort of religion would be a good example. Another would be "look at this wonderful world of ours and consider how inadequately science tries to explain it all. The only possible explanation is that a supernatural being put it all here." Spot the flaw.