I'll also take a stab at helping you understand what happened. I am not a moderator on Photo, but I am a moderator on another SE site and have been around for a while. MattDM behaved properly and is knowledgeable about what you were asking.
Your initial question was not clear exactly what you were asking due to grammatical problems, but the general question was still clear. He initially marked it as "unclear what you were asking" because it was hard to follow.
Then, upon realizing that we have a question that covers file recovery (which is the same for either a corrupt card or a formatted one), your question was suggested as a duplicate of the question about how to do file recovery on a memory card. The answers are in fact applicable to your situation, so it is a good match.
Then, after the community (it takes 5 people or one moderator agreeing that the question is a duplicate) agreed that the question was in fact a duplicate, a moderator (John Cavan) took care of merging the questions. This moved the comments and existing answer from your question and placed them on the main question. The question and comments on the answer weren't removed from the system, they were simply combined with the other question.
This is a good thing because it means that now a) there are more good answers to the general question on file recovery and b) there is now a second way for people to find that question by searching. If they come across your question or the original question that has the answers, they will still get to a great set of answers for the problem.
As a community edited system, any member that is sufficiently involved earns the ability to edit posts or suggest closing or deleting a post. Even users with low reputation on the site can suggest edits to a post and have the larger community approve their edit if it is an improvement. This is helpful since it allows for a cleaner, easier to read site with higher quality questions and answers.
There is also a publicly available revision history available for anything the community does and most things moderators do, so even if someone makes an edit, your original version is never lost and you are able to revert edits made by other users if you don't think they are accurate to your intent.
Further, if your post is closed, you can edit the post to fix the problems and it will automatically be submitted to the community to vote if it should be re-opened.
The only thing really special in this case is that it was merged since there was a good answer. A merge is a moderator only action and can't be reversed. The lock is also placed automatically since the question has now effectively been rolled in to the main question and any answers or comments should happen on the main question.
I hope that helps with your understanding of how Stack Exchange works. Please feel free to comment on this answer if you have any more questions and I'll try to get back to you on them.