I can't help thinking that the theory that PVC sleeves cause damage originates from this document, which is clearly talking about inner sleeves (ie contact damage):
The Care and Handling of Recorded Sound Materials By Gilles St-Laurent
National Library Of Canada January 1996
Do not use paper or cardboard inner sleeves and do not store records without inner sleeves.
Use soft polyethylene inner sleeves. Do not use record sleeves made of PVC.
Remove grooved discs from the jacket (with the inner sleeve) by bowing the jacket open by holding it against the body and applying a slight pressure with a hand. Pull the disc out by holding a corner of the inner sleeve. Avoid pressing down onto the disc with the fingers as any dust caught between the sleeve and the disc will be pressed into the grooves.
Remove grooved discs from the inner sleeve by bowing the inner sleeve and letting it slip gradually into an open hand so that the edge falls on the inside of the thumb knuckle. The middle finger should reach for the centre label. Never reach into the sleeve.
To hold a disc, place the thumb on the edge of the disc, and the rest of the fingers of the same hand on the centre label for balance. Use both hands on the edge to place disc on turntable.
The problems others have reported in this thread all seem to point to problems with humidity/heat during storage (not that his makes it any less serious)? Bob Stanely (who he?) doesn't even claim to have suffered from the problem himself, just that 'some people swear' that they do and he 'isn't risking it'.