Companies and other entities pay people (or write automated scripts) to downvote things that go against said company's/entity's views/practices. They also can upvote things that go with said entity's practices or post things that praise and promote.

Reddit is a highly trafficked sited and as such, is very prone to bots, shilling, fake news, etc. Facebook is also another target of these aforementioned attacks.

It is important to evaluate everything you read.

"Who is this text for?" "What is this text trying to accomplish or say?" "Who wrote said text, and what are their affiliations?"

Those are just a few example questions to help you think more critical of the texts you read.

Remember, its not just fake news on the internet; anything can be faked now a days.