In the general case, maybe a little bit, but mostly not. In the specific case, not.

Baader-Meinhof is about an illusion of high frequency. This specific case (iran + github) is direct coincidence. The general case of the poster above (topics bubble up from multiple sources) is not, because topics can be demonstrated to follow patterns of relatedness (there is a term that I forget) and :. the frequency is not illusionary.

Of course, that supposes the pattern noticed is the pattern that was genuinely in the articles. Baader-Meinhof will apply to anything the user misidentifies. I presume that the direct links between groups of articles (ie, the ones that caused them to be written or posted) are much more prominent than the "background" noise of links that the user will Baader-Meinhof.