Trolls and crap content? Aren't you being overly broad here? I find the r/swift and r/iOSProgramming communities pretty informative. And the r/ProgrammerHumor is good for a smile.

https://www.reddit.com/r/swift/ https://www.reddit.com/r/iOSProgramming/ https://www.reddit.com/r/ProgrammerHumor/