When is opinion too much opinion?

Recently, I came across a conversation about someone where the person seems to have passed a very opinionated comment on something very irrelevant which hurt a lot of people. And I agree that the comments were a little under the belt.

Is it fair to pass judgements and opinions and advice just because? People usually are tuned with other peoples sentiments and yet, while passing a comment on something, it almost seems like they are bypassing any feelings or tact. What is the point in passing comments which you know do no good, spoil relationshops and make everyone uncomfortable? Do people usually do that out of a superiority complex or the other way, to avoid feeling inferior? In which case, it is usually silly, because they make it so obvious...

There I go making a judgment..and yet I like to think of myself as fair for most of the time..