Why is referring to an OP's previous posts considered A Bad Thing?

[JFDIYOLO]

Just that, really.

AIBU to think it makes perfect sense and allows a more realistic response?

An OP posts a question, asks opinion and advice.

People do them the courtesy of spending time thinking about it and writing an answer.

A poster mentions they've looked at their previous posts which contain a lot of pertinent info, back story, repeated incidents etc etc which weren't included in the current post.

This informs the advice they then give.

Why have I so often seen others haranguing them for going down the previous (entirely public) posts?

It seems very sensible - to get the facts before wading in to answer something that only gives a fragment of the true picture.

What do you think?

Just search for their username in advanced search

I see your point about background being useful for advice in terms of continuity. But as others have said it often seems like people are trying to fact check and accuse OP of lying. I’ve also noticed comments like, “you posted about this before and were given advice then” as if wanting to raise an argument issue a second time is tiresome, when people could just scroll past. Sometimes people need to talk about things more than once.

It often seems stalkerish as you said. It almost always comes across mean spirited imo

Because it's quite often done to try and humiliate or undermine the poster
Some people get real glee from pointing out a contradiction compared to a previous post

It can be quite unpleasant at times

Exactly! It’s never done in a helpful way, more of a, ‘you’re lying and here’s the proof’ kind of way. It’s quite strange actually