I know very little about this field of study. I do know that a university local to me have recently begun bioinformatics electives. I'm sure this happens every term and isn't unique to this establishment. The students have no Perl (or in the majority of cases any programming) experience, the course is very poor but this is something which is being addressed in the near future. I don't agree that all of these posts are coming from 'researchers' (or people pretending to be researchers) or that everyone in the field must be 'really, really smart'.
I'm sure people who spend long periods of time here begin to notice trends in popularity of certain topics, bioinformatics being one of them. To me this is hardly surprising. Like a lot of people using Perl to solve a problem, they're not computer science students, or employed to write code they're just trying to achieve a goal. Some could care less how this is achieved.
When people show up here with a vague specification or check list of goals they want to achieve I tend to advise the walk "before you can run" approach of learning the basics of the tools being used. Sometimes people don't want to hear this, often because they just want the end result rather than to learn from the journey. I find failure to do so results in thread after thread of the same question being posted, see davidos reply to How can I count the number and kinds of letters at 1st, 2nd and 3rd positions of 3-letter words in a string?, which is one of the threads you mention.
To address some other points you raise, not everyone speaks English fluently, they may not be writing papers or sitting courses in English, simply trying to ask questions in English here. See List_of_languages_by_number_of_native_speakers. There may be a shortage of people working in this field, even if this is the case it doesn't necessarily mean that these questions are from industry/academic professionals.