There already is a tag blacklist system. There is no such tag blacklist for the specific tag homework on this site. Blacklists for the system should be evaluated one-by-one. Note that there's also a burnination system, which deletes the tag from all questions in one blow, so we don't have to go through and remove it manually.
There are various levels of dealing with bad tags:
- Edit the questions with the tag. I've updated the list of meta tags to include post counts, many of them can be trivially dealt with by hand. Note that the tools and policies originated on Stack Overflow, which has over 2 million questions, so dealing with 20 questions is trivial. While doing this, consider that having bad tags is an indicator for bad questions - Consider whether the body and title need editing, or if the post should be closed entirely. You want to leave high-quality questions behind you.
- Burninate the tag if the remaining questions appear to be well-tagged and high-quality, or so numerous that they can't be edited in bulk.
- If, after burninating and manually clearing, the tag comes back from the dead (remember that 500 rep is required to create a tag, so this shouldn't happen in most cases), then we blacklist.
Particularly egregious tags may start further in this system, but this is a good general case.
You can propose a tag to be blacklisted via the tag-blacklist-request tag. For good examples of this in action, search for
[tag-blacklist-request] [status-completed]; for example here on MSO. There are currently no tag blacklist requests on meta.electronics, so it's unsurprising that you were unaware of the system.
Tag blacklists are typically used for meta-tags, as described in the blog post. Examples of meta-tags would be the contents of the list at What meta-tags on E&R should be axed?, which includes your listed tag beginner.
Other bad tags are those which don't helpfully describe the question given the context of the site, such as programming on Stackoverflow, or electronics, electrical-engineering, electrical, or engineering here. Unfortunately, electrical is the only item in that list which has no questions. None of these should exist.
In summary, I'm terribly sorry for the abominable state of tags on this site. Yes, we need to work to improve them. Yes, blacklists are available.