I think there'd need to be evidence of a pattern of multiple accounts for any claim of artificially boosting ratings to hold up.
A single rating isn't going to make much difference, and it seems much more likely to me that Mr Clark just personally likes some of the wines
Vinomofo sells! (Shocker.) Counter conspiracy theory: maybe mof_ only sells them because he rates them five stars?
Using Vivino (or cellar tracker etc.) to track wines is hardly unusual, and 47 wines rated is probably a pretty standard number, even on the low side, for someone relatively into wine - it's certainly a lot lower a count than you'd expect if he were intentionally 5-starring everything mof_ sells.