Just because you add a tag to a question, doesn't mean that you are actually that thing. I could add a tag of intel-cpu-designer to my questions, but that doesn't automatically mean that I work for Intel designing the next CPU instruction set. People could easily abuse this by adding tags like power-user when they are in fact more of a newbie.

Tags are mainly for the search function. When visiting the site, what would be the benefit of trying to search for questions asked by people of particular backgrounds? Just finding a question which addresses the same subject as your own question is almost always going to be good enough, if there's an answer associated with the question. Doesn't matter if the OP was a newbie or an Intel instruction set designer.

Having questioner tags in the tag pool would conflate who's asking with what the question is about. First of all, you can only have 5 tags on a question, so if you use one or two tags for your background, that leaves fewer tags to be specific about the question's subject. Also, some tags could easily be confused between actual subjects and people; for example, the name of a profession could possibly also be the name of a program.

Stating in your own words what your background is, and what your level of expertise is relative to the subject matter of the question you're asking, is much more precise when you simply write this information in your question. People will sometimes edit your question to delete nonsense like "My mom is sick and needs this so she can feel better" or "Thanks! -Tim", but if you provide 1 to 3 sentences describing your knowledge of the subject matter, I cannot conceive that this would be edited out and deleted until at least after your question has been successfully answered.

Lastly, but importantly, Super User (and the other Stack Exchange sites) are not primarily about you. The actual people participating in a question and answer dialogue are actually in the minority; they're like actors on a stage. The purpose of the question and the answer is more for the audience -- all the thousands or millions of people out there with the same question who will Google for this and find your question (and the answer). You are a minor, but significant, participant in the system (as if to say, "congratulations, you asked a good question; have a cookie few rep points!"), but by far the most important "participant" are the legions of people who simply click the link to your question, find a good answer, use it in their life, and move on. If you are able to ask your question in a way that elicits at least one decent to good answer, I don't think any future visitors to the question will care one way or another what your level of experience is or what your qualifications are. If you simply ask the answerers to "please state your answer in terms that a new computer user could understand", the questioner tags and other stuff become mostly redundant.

You mentioned that people are being rude to you. If this is indeed the case, you should not be searching for a technical solution to your problem. Simply flag the offending comments and/or answers for a moderator's attention. There's no need to respond to their rudeness. They may be acting rude because they feel like you are asking a question that's way over your head (like trying to build the roof of a house before you've even laid the foundation), but even if they feel that way, they should just tell you that (cordially), rather than insulting you. Then they can provide you pointers to the foundational knowledge you'd need before you can begin to tackle the subject matter of your real question. If you regularly encounter users behaving this way, just flag it. It'll be taken care of.