There's a lot of bots on here like any other social media but you'd either have to follow them or they'd have to exploit a tag you follow in order for them to appear on your personal feed. 

 You can get banned on the relays. But they don't even ban Child Porn so ..... 

 ☠️ 

 Yes, that's why it's important in the future that there's more than just a few big relays that everyone follows.