Being nice and respect for each other are both very important. If this needs to be put in a single sentence, it would look something like
“You must be able to be who you are, unless that prohibits others from being themselves”
As a set of rules it could look like:
- You are identified by all the aspects that are you, including beliefs, world-views, race, sexuality, likes and so on.
- You have the right to live according to the above, unless that would result in limiting that same right for others
This may be a little abstract, so let's enumerate some consequences.
- You should not judge others and must not attach consequences to that judgement.
- Inflicting harm to another person is only acceptable if that person agrees.
As this is generally not the case, it should not be done. For example: killing and stealing is generally not desirable. Stealing is meant in the broadest sense and includes swindling, deception, taking away opportunity, bringing disadvantage and fraud.
- You cannot say that harm is done to you just because someone else does not live according to your standards.
This would be judging someone else by your own standards.Naturally, you can ask someone to behave differently or in another place, however, that goes both ways. Be nice, live and let live!
- The constitution and law should make sure that the above rights and limits are enforced
More elaborate ways of describing this are the cornerstone of many books of Faith, though these often define additional guidelines. These additonal guidelines are often understandable in a contemporary context. If it turns out that certain foods or beverages are not good for people1, it makes sense to forbid them. As long as the additional guidelines are kept up-to-date with reality and otherwise not forced upon others, there is absolutely nothing wrong with faith.
When an authority cherry-picks guidelines, makes them hard-wired and they are forced as the only Truth upon followers, we have a religion. And often it considers “others” – non followers of this particular religion – as evil, stupid or lesser people that need to be converted.
Religion is a tool for political ends: instead of truth, the political ends are its goal and the followers its means.