I understand that one cannot draw a line to clearly separate categories from categories, but that doesn't mean that categories don't exist.
As to the definition of these terms, I was only thinking of their "common sense" meaning.
What is the common sense meaning of bigotry?
There’s plenty of political discussion on this site (the top 5 includes about ongoing EU legislation). There’s obviously some pretty heavy-handed moderation of it (not that it is inappropriate for this particular community), but no general forum will get very far with such a rule.
Reddit is a general forum. There are subreddits that are moderated heavily and need to be, and those that are barely moderated. There are subreddits for porn and politics because people want those. Reddit replacement needs to support multiple communities and varying moderation.
Grey lines are hard (impossible?) to enforce.