Simple the apostle was originally designed to use either a different vow, or a number of generic vows and they never bothered to change the armor thing after switching over to VoP.
Even if you could convince someone of the specific to general rule applying (which it doesn't since the feature is in fact non-specific thus the problem). You still can't own the items so you'd be at best able to borrow something for a while until the DM decided you were pushing the limits of the term.
Even if you could convince someone of the specific to general rule applying (which it doesn't since the feature is in fact non-specific thus the problem). You still can't own the items so you'd be at best able to borrow something for a while until the DM decided you were pushing the limits of the term.