I regularly see single and double quotes used interchangeably and think nothing of it. I still fair to see your point. I generally prefer to use double-quotes for things like actual quotes or irony, and use single-quotes for things that don't justify double-quotes.
The fact that you use quotes incorrectly (at least as per British English, where the BBC is located) isn't really relevant — the BBC News site is written by actual, trained journalists with subeditors and editors, so you can expect them to use quotes correctly. I'm not even really sure why you think it is relevant. So my point is exactly what I've said it is, even though you disagree, i.e.:
Thomas Harte said:
maybe 2008 was the year that, per the BBC, the software meaning of bug stopped being recognised by mainstream society?
I think [mainstream society does know what a software bug is], at least to the extent that single quotes in a heading like that just look like someone meant to use double quotes and messed up.
Again: I think mainstream society knows what a bug is. I am therefore surprised that the BBC suddenly think they do not. Given the wide knowledge of the meaning of the term, I'd go so far as to say that the BBC's use of single quotes looks almost like they meant it to be a quote but for the fact that single quotes aren't used for direct quotes like that. However, as I've previously said, it is obvious from the article itself that they have used single quotes correctly and simply believe that people do not know what a bug is.