In this other informative website 'tightlycurly.com', there is an exhaustive ingredient list, TightlyCurly.com
which claims that PVP builds up and should be avoided altogether. However, I found this article The Nitty-Gritty Details About Hair Gel
in this website which claims PVP is water soluble. Also the CG routine doesn't talk about avoiding PVPs and many CGs swear by products like Organix Moroccon Styling Perfection Cream which has PVPs.
Again, in 'tightly curly' , Dimethicones are considered good, as build up of over 1-2 years can be removed with one mild wash of cocobetaine.
There are lots of curlies who swear by either of the methods (CG vs TC), so what are your opinions on PVPs?