These are the rules for lemmy.world
Each instance has its own rules, but you have to follow the rules of the community you're posting in. For example, burggit is where I'm commenting from. It has very loose rules for discussion, but not against other users. Since I'm commenting in the lemmy.world community, I should follow the community's rules.
It's also worth knowing that depending on your instance, you might not see people replying to you. Scroll down to "instances" to see if your current instance has any blocked.