Spewing invective against people simply due to their membership in a particular group, providing disparaging comments in a rude manner simply because you disagree with them and generally behaving in a manner that one would never consider were one face-to-face with the same person does not constitute "dissenting opinion" to me.  Dissenting opinions can be expressed in logical and thoughtful manner by addressing the point being made through fact and argument.  Ad hominem attacks are not dissenting opinions.