That link doesn’t prove whatever you think it’s proving.
That link strengthens my argument that we're assuming because it's open source that the code is less likely to have security issues because it's easier to be audited, when in truth it really just depends on the maintainer to do the proper level of effort or not, since it's volunteer work.
When someone suggested a level of effort to be put on code checked in to prevent security issues from happening, the maintainer pushed back, stating that they will decide what level of effort they'll put in, because they're doing the work on a volunteer basis.