Attack the argument not the person:
Not everyone has yet realised that their beliefs are based on what they have been exposed to and not necessarily reality. People hold a passion for what they were raised to believe. Respect that passion and the person, even if you think they are deluded.

For the less able to grasp empathy this means do not express personal insults and threats.

Be nice, try to understand others, none of us can help the way we think. Some of us cannot help the way we act. Our sense of right and wrong has been shaped by the societal structure in which we were nurtured to adulthood.

Do not post offensive material:
Now what is offensive? Again a person being offended by something is related to the environment or culture in which they were raised. One would hope that there are something’s that most humans, if not all, will agree on as being offensive.

I really don’t want to enforce censorship, so be nice to each other and show respect. Critical argument is always better at finding the truth than censorship.