Actually primers/cements have a lot of tetrahydrofuran (THF) in them. Plumbers have been using them for years but PVC is typically used for drain lines, not drinking water.
THF is "relatively non-toxic" but not really good for you...it also leaches from the cement for some time after fabrication. Some environmental clients of ours won't even let our treatment systems be constructed with old fashioned primers/cements. This is because the discharge levels of THF coming out of the system exceed drinking water levels for months and months following system start up.
Are you going to get ill, very sick, and/or die from the minimal dose (you are not drinking lots of water from the carboy cleaner and you are probably letting the carboys dry well before use)? Probably not, but something to think about.
I don't have it anymore, but I used a bottle washer out of PVC with glue for years. I feel fine.