I wouldn't say it is rude per se, but perhaps some comments are in place.
Physics is a subject that grows exponentially fast, in the sense that new knowledge tends to use a great deal of previous knowledge. For example, if you ask a question about General Relativity, people will assume you are familiar with, say, Electrodynamics.
This sometimes means you might ask a question about GR and the person answering will give an answer that uses concepts from Electrodynamics you might not be aware of. I don't find it that unusual for someone with little physics background to ask about some really complicated stuff and get a complicated answer. Of course, this might lead to many follow-up questions to understand the answer.
This has some issues. Many of these follow-up questions might be also quite complex and impossible to answer in a comment and deserve a post of their own. In other cases, the follow-up question might not be suitable for a post because it is, say, the third class of an Electrodynamics course. In such a situation, I find it reasonable to expect that either you can understand the concept with a Google search, or you lack the proper Electrodynamics background, in which case we have a completely different problem.
This different problem is that the answer might have no chance of being useful for you right now. In some of my questions, I have received answers that are great in hindsight, but I definitely had no way to understand them at the time I asked the question. A way to avoid these issues is to try to make clear in your post what you expect of an answer. For example, it seems to me that the majority of users on this site are currently pursuing an undergraduate degree in Physics or already have one. Hence, it is really common for answerers to assume this. It is, of course, completely okay for someone on high school to ask questions in here, but making clear in your question that you expect an answer accessible to high school students will lead you to much more useful answers.
For example, the Relativity example I gave. Relativity is an interesting subject here because there are questions asked by people working with the theory, and there are questions asked by people who know very little physics and are just curious about the Universe, and everything in between. And sometimes it is not clear from the question alone if the person expects an answer for a layman or an answer heavy in differential geometry. Depending on how I answer, the answer might be extremely useful or useless. Hence, adding context about what you expect in an answer might make the answers way more useful and minimize the amount of follow-up questions necessary.