THE SHORT VERSION:
Don’t use any of the hashtags on this list.
Instagram automatically lowers your posts reach for using these blacklisted hashtags.
Why? They don't like content like that being on their platform.
It's not just the post that’s adversely affected with less reach from blacklisted hashtags - your next few posts will be negatively impacted too! This is because your account will be flagged as a user of blacklist hashtags.
Instagram doesn’t like porn, nudity, or aggression.
How does it prevent it? Two ways:
(1) Image recognition - If after scanning your image Instagram identifies something inappropriate such as a nipple or penis, your post will automatically get reduced or no reach.
(2) Hashtag use - If you use certain hashtags, like the ones on this list, your post will again either be completely censored on hashtag feeds or will be shown minimally (if at all) on both the hashtag feed and your followers standard feeds. Once you’re listed in the Instagram database as someone who posts like this, your future posts are more closely monitored (algorithmically though, never manually). Think about it like TSA’s watch list! Use one of the blacklisted hashtags and you're automatically put on the No Fly list.
Here is a Huffington Post excerpt that explains this perfectly:
“For example: You can post a picture of your cat using the completely banned #dick hashtag (assuming your cat did something to deserve it), but tapping that hashtag after you publish the image will lead you to an empty page, like below:
Now, if you had posted that same picture of your cat to #Kansas, you might find that it doesn’t appear there while other photographs do. Instagram will partially censor a hashtag if it’s been recently used with problematic images. The social network typically has both a “top posts” and “most recent” section for hashtags.
But if a hashtag is being abused, Instagram will remove that “most recent.”
NOTE: For those that know the term ‘shadow ban’ - this is not a real thing.
Fake news in social media is a thing! Shadow banning was created by the media. It’s actually just a bug with a few hashtags that happens often. This has been confirmed by multiple Instagram official sources.