I am a beginner to this stack exchange and I am holding account in 21 sites of stack exchange. I ask a question, I get positive comments and a valid answer . With that am offered with down-votes too which reduces my reputation. When a person gets a valid answer, shouldn't the down-votes go meaningless? Why those people who down-vote do not leave comments explaining why they down-voted for questions which has an appropriate answer ?
As one of the people who sometimes downvote without any comments, I will try to list for you my personal reasons for downvoting:
1: You are too political, borderline trolling. If the question is, say, on gender issues or women's rights, I downvote answers based on personal opinions. Example: "Women should know their place" answer on this example gets downvote for me.
2: Your answer is too simplified or too hand-wavy Again, if I ask about, say, generational ships and how to survive 600 years, I tend to downvote answers saying "Just put them into a freezer."
3: You answer something I did not ask about Example, if I ask about using poison, I do not like getting answers that say I should use a bomb in that scenario.
4: I am not really sure what you are saying: Although I am a non-English speaker myself, I can understand some typos. But if I cannot understand, I downvote. However, I usually comment when this is the case.
They are just internet points
I know it is easy to say when I myself have 12,196 of them and you have just six. But remember, it's just virtual points, nothing more. Whenever you get downvoted, take deep breath and try remind yourself of this.
Post specific examples here
The point that you have just six internet points can have an effect on people downvoting you. I have been in several online communities, so I can safely assume that someone looking down on new users can happen here, as it was common in several communities I have been part of.
This is what the Meta is here for: Post links to specific question or answers which got downvoted. It will get more attention from moderators and/or experienced users.
My personal experiences with the Worldbuilding community is that it is a welcoming community full of people willing to help you provide better questions or answers and get more internet points.
I only see one question on your account. In the case of that question they most likely also started a close vote, with the close vote reason being the same as for the downvote: Your question is not actually about worldbuilding.
If you read the tour and in particular the sections about what to ask and what not to ask that should help you consider how to re-ask the question in a way that will be better received.