I personally have some mixed emotions about the stunt itself, but I tend to agree: It achieved its end goal of fixing Rails, which in the long run is a net benefit. The short run isn't so clear.
Based on the description of the situation, it seems like two outcomes were likely: Homakov could have just kept complaining until he was blue in the face or got bored and gave up. Or, he could be provocative and effectively publicly shame the developers into realizing they truly had a problem.
Sure, boiling it down to those two likely outcomes misses a sea of other possible outcomes. I'm not trying to commit the fallacy of false dichotomy here. But given an apparent choice between these likely outcomes, I can understand why public shaming in this way seemed attractive to Homakov.
It all feels a little childish, really, but at least the defaults are saner and the glaring hole in GitHub is closed. Now all the other Rails sites need to go fix themselves. Wheee....