I mean to me the issue isn't quality so much as it is "is it clear that, if it's a bad graphic, this person is learning from it and can be expected to at the very least get to the point where they're making something presentable if they're at it long enough". People SHOULD be encouraged to get into making graphics and if that means some legitimately awful stuff gets approved at the start, then that's what that means.
If they continue to put out legitimately awful stuff, then yeah, I'd agree with you. Some updater should eventually end up linking a resource thread and saying "I'm not going to continue approving these unless you can step it up". But if it's just a question of "starting to learn the software" it's not like we shouldn't be more lenient and accepting. Not everyone has to be a sig god--in my own personal experience, it probably took a year between my first graphics and me making anything that I'd actually put in my sig. I certainly wasn't doing them every week but I was taking steps forward--and if someone told me after my first few awful ones that I wasn't good enough to get approved for 6, I'd probably just give it up entirely.