A.
Freeper X: I am a Protestant.
Annalex: Protestants are heretics.
And, if that is still not allowed,
B.
Freeper X: I am a Protestant. What do you think of Protestants?
Annalex: Protestants are heretics.
I am not trying to tease you, -- these are scenarios that are hard to avoid.
Also, a perhaps wider question: at least for a Catholic, "heretic" is a technical term, a rough synonym for "non-catholic". It does not imply hatred at all and should not be listed alongside examples like "child molester" or "liar".
However, if Freeper X makes the thread "about" himself by constant complaining that he was called heretic indirectly, then Freeper X would be warned to stop making the thread "about" individual Freepers - in this case, "about" himself.