I get that's the logic but I think it's completely stupid. If someone is "mediocre" enough to scrape by that implies they are competent enough to get the job do

I get that's the logic but I think it's completely stupid. If someone is "mediocre" enough to scrape by that implies they are competent enough to get the job done. If they are not able to get the job done, then they are by definition a charlatan and will be let go.