Get Reddit Enhancement Suite and start tagging posters. Fully ten percent of /all is literally one account posting karma bait.
I've also seen entire threads get "replayed". Bots will post highly upvoted comments from the last time a link was posted etc.
Nearly everything that makes it to the front couple pages of /all is posted by people pushing an agenda, or worse, literal Russian accounts fomenting hate. Remember, their goal above all else is to make you angry, tired, and get you to give up on functioning democracy. Lots of people on the left and "democrats" are fighting with talking points straight out of the kremlin. That infighting is the point.
Everything you see on reddit is meant to make you angry. Someone will mine Twitter for the most hateful nazis shit/most objectionable "I hate men" post, and post a screenshot on reddit as if that's a meaningful representation. This is intended to piss you off, because you will "engage" more if you get pissed off.
The internet doesn't want you to be happy or successful or informed because it is literally less profitable.
There are entire popular subreddits that are mostly agenda posts, either literally part of an operation, or outright useful idiot sycophants.
You almost cannot make it to the front page anymore without a bot farm to to get the "momentum" going on your post. Otherwise it just cannot compete with the manipulated posts.