There may be some users who have incorrectly used sequel when they meant sql, but there have also historically been plenty of correct taggings using sequel. With the approval of this synonym, data has been lost.
I used to browse http://stackoverflow.com/questions/tagged/sequel and see a list of reasonable questions about the library. Now I get a flood of information n00b questions. Any questions that were (as fashion has it) only tagged sequel, but didn't use that word in the title or question, are now quite confusing.