It's not the site's issue, it's Stallman. Even if they didn't intend for it to be a strict Open Source site, it has Open Source in the name which Stallman would

It's not the site's issue, it's Stallman. Even if they didn't intend for it to be a strict Open Source site, it has Open Source in the name which Stallman wouldn't participate in. The same way Stallman won't participate in (at least at the time of writing this comment) shows or conferences that only use Linux in the name and not GNU/Linux. For example he won't go to something like Ohio LinuxFest and the Linux Action Show had to rename itself the GNU/Linux Action Show to get him to come on. For some people the work of changing the name is worth it, for others it's not worth the hassle.