lainchain has a fairly civil and decent programming board, slanting towards beginners but still friendly.
You shouldn't cut yourself out over "invite-only", especially when the site itself tells you where to get an invite. It's a small speed-bump to keep out folks without basic politeness and problem-solving skills, not some sort of elitist thing.
The cold fact of the matter is that any community that pitches a wide tent and allows for everyone to join and talk about whatever is going to be unable to maintain a good signal-to-noise ratio...communities that wish to avoid that need to remain focused and conscious of what content they want and do not want.
It's possible to say "this is content that doesn't belong here" while at the same time not painting the content or submitter as deplorable.