I’m seeing a recurring issue that I get downvoted for that never seems to get directly addressed, and I feel is kind of biased. If someone asks for what the Catholic Church says about a subject, obviously it needs to be an answer from the catechism or other relevant sources. However, I see a lot of questions that ask simple historical or Biblical questions and throw the words “according to Catholicism” or adding the tag “Catholicism” to the end, and I get downvoted if I answer them because I don’t cite Catholic sources. Catholicism isn’t supposed to be in contradiction with the scriptures. If someone asks, for a very simple example, “how many people does the Catholic Church say Jesus fed in Matthew chapter 14?” The best answer is “5,000 (Matthew 14:13-21)”. There’s nothing specifically or inherently “Catholic” about the question. If the question can be directly and thoroughly answered outside of specifically Catholic resources, and the person adds “Catholic”, it’s hard to feel that this is anything more than saying, “I have a question, but I don’t recognize the authority of any Christian or Christian group that is not Catholic.” (Or Methodist, or Episcopal, etc. - not trying to single out only one group) It is, after all, a stack exchange called “Christianity”.
Many Protestants agree with you and in a perfect world you'd be right. The problem is twofold though:
A person of a given denomination asking a question can't always know ahead of time whether their question is generic enough to be answered by anyone
Some denominations teach that they are the only sure interpreter of the Bible, therefore if you ask a question, answers have to not only sound correct, they have to be sourced correctly.
The fact that the website is named Christianity is confusing to lots of newer users. It's about Christianity, not Christianity itself. The site was borne out of a QA site for programmers. As a corollary, if you asked a question about how to do a thing in Java and someone said, here's how I'd do it in Fortran - that would be not terribly helpful.
You are right that some questions seem to tack on the Catholicism tag, I think those ought to be evaluated by some of the higher-rep Catholicism users on the site and we should close questions where Catholic Doctrine has no particular special understanding of some piece of scripture.