A moderator deleted my accepted answer and I wanted to know why it got deleted. I've read the FAQ but I don't think I've crossed any lines.
You posted the same exact answer on multiple questions, that are in fact almost exact duplicates of one another.
This makes merging those duplicates into one tedious, as your answer would appear twice, but only once as accepted. When the same answer sufficiently solves two questions, you should simply answer the question with the best detail and flag to let us know that the other(s) are duplicates. We can then evaluate them and possibly merge them all together to create a great canonical post.
The moderator that took the action can probably explain why they chose one over the other to delete (or swap them, restoring one and deleting the other), but that's really incidental at this point. Depending on how a future merge is arranged, you may not ultimately maintain the accepted status. That's .. just how the system works, it's designed to put overall quality for visitors first.
When you post identical content on different questions, the system automatically raises a flag for us to investigate it. We'd rather not have multiple questions with multiple copies of the same answer to maintain, it's better to just merge things together, or (on our part as moderators), make sure that duplicate content isn't needlessly complicating a future merge.
You copied the content, word for word, from one of your other answers and pasted it in an answer to this question.
It should be obvious why your post got deleted, but just in case it isn't, I'll explain. Stack Overflow exists to make the Internet a better place by eliminating noise. When you or I search for a problem we're facing, if we land on Stack Overflow, we're more likely to succeed if we don't have to comb the depths of the site and find duplicate answers. This not only adds confusion, but clutter.
Instead, the correct action would have been to flag the post as an exact duplicate, and since you just posted these answers within an hour of each other, you obviously knew it was a duplicate.
The advantage of closing a post as a duplicate is that all of the answers can be merged together into a single thread, making it easier for future visitors to find all the helpful information in one post.
so, in the future, if you see a duplicate question, flag it. This will help ensure that all the answers, and the question, is useful. Hope this helps!