Those were both third-party modules for Django (albeit popular ones). But at best, this means that Rails devs have known since Nov 2011 or so that YAML code should be carefully audited, especially since there was no equivalent in Ruby for Python's .safe_load (http://stackoverflow.com/questions/14348538/is-there-an-equi...).
I don't mean to beat on the Rails guys too hard though, they're off shipping stuff and I'm not and I'm not very fond of those who criticize while a safe distance from the action. But I think it's fair to say that this could have been foreseen earlier (or much earlier, depending on who you ask).
Wow. Not sure how they managed to miss the big warnings about yaml.load. Notice, however, that unlike Ruby's YAML parser the Python one does actually have a yaml.safe_load.
I checked the article, and that bug was similar in the relevant sense. It was a security bug related to hashed messaged authentication codes, a class of security exploits related to very non-trivial issues in cryptography. It was not comparable to "let's allow an information-file parser to execute arbitrary attacker code".