Personal questions are too specific to you. People prefer to deal in more fundamental ideas that can be applied to many things. Honestly, it get's fkn annoying seeing the countless "does he like me" questions - especially since the answer is usually something like "try talking to him, dingus" because initiating anything is beyond the realm of female capability apparently, but I digress. The more personal and specific you get the less people are going to care to sit through that and invest thought into it. They are less likely to have experiences that are super-specific to your situation.
Sadly, most people can't be bothered to read through a whole long text over 1500 letters. And usually they'd have to respond with a whole paragraph and not everyone can be bothered to do that. And sometimes the question is too complicated or too difficult to answer, or it doesn't have enough info do make a clear answer/judgement, or the description is just confusing and all over the place. There are many reasons, but most of the time it's because they can't be bothered.
It could be when someone under 18 ask a question that someone over 18 or older can feel like you shouldn't be worried about nothing like that. You are too young to be dealing with things like that and you should be focused on school. I mean we all need help so it just up to the individual how they judge people age and question.
It could be the way you're asking ie Great Wall of Text, "what does it mean when he says the sky is blue?", or "does he like me when he stares in my general vicinity for.2 seconds?". Those are all question types that just aren't interesting and tend to have tons of follow up questions that are really annoying.
It really depends for me. There are questions that come up with topics that have been discussed on here hundreds of times, and I usually ignore those. Like... I see about 10 "does he/she like me" posts every day, and I only respond to those if there's a poll where I can just say yes or no. More complex questions, I will read and respond only if I feel I can give insightful, sound advice on. If I can't I won't post anything.