Most people have a range of interests, and most interests have a range of people. If you follow people you'll see stuff you don't like, and if you follow hashtags then as soon as they get popular they get hijacked by entryists. Plus the site is optimised for ragebait - that's the natural result of the emphasis on short posts and the algorithm that optimises for "engagement" - so even if you're following the right people and the right hashtags you'll still see the worst parts of them.