I think it’s the same as in real life.

Most people are good natured and kind but some simply aren’t. So it’s no different from real life. Sadly some people just suck. Also I think that people who keep bugging you for no reason just aren’t well. They aren’t well enough to manage proper human interactions and properly function in a society. They need help, not a punishment. Pray that they get the help they need.

But if you could demonstrate that this person is deliberately harassing you or you suspect they do so, it’s wise to report it and mods will certainly look into it. Even if a person is unwell, they aren’t allowed to harass others

Of course some people just don’t know they are on ignore. But I have a feeling that honest mistake is not what’s being discussed here