You're clearly confused. This conversation is about 4chan jannies, not reddit moderators. They don't ban you for posting racial slurs or fascist rhetoric, or any other traditionally offensive material.

Make a thread about Chinese naval buildup or related strategic developments in the Pacific on /k/; banned for "off topic". Get into an argument with a user who turns out to be a janny; banned for "trolling". Respond to a funny /tv/ thread memeing on some TV show, banned for "responding to off topic threads". Post a dozen pictures of rockets in the spaceflight general being raided by some /pol/tard who thinks space is fake, get banned for "spamming".

The jannies are arbitrary and capricious. Three day bans can't be appealed so they hand them out like candy.