Starting a new thread, because Google apparently thinks the original thread from May is too old to reply to. I swear Google assigns their stupidest employees to Group software development. And my ISP dropped Usenet so a real newsreader is out. Sigh.
Anyway, I went to Home Depot, consulted with the nice man in the paint/ glue department and used GOOP Plumbing, which comes on a purple card and set me back about $5. I followed the instructions which are basically to apply to both surfaces and wait a few minutes. So I put some in the hole, and applied some to the shaft of the new shelf stud, waited a few minutes and inserted the new stud.
Then we waited one full week before putting any weight on the stud. That was probably excessive, but given the lower temperature, we wanted to be sure the thing really had time to cure. Plus it hardens by exuding solvents and the refrigerator wall is kind of an enclosed space for solvent emissions. So anyway, we waited a week.
Then we reinstalled the shelf and hung the top crisper from it, and it's been holding up solidly for a couple of months of use now. So the Goop:Plumbing seems to be a good choice.