There's nothing wrong with the price or the certificate.
You can take the certificate as you like. It is a dealer/seller's guarantee. It was not probably not considered at all in the bidding except that seller states it is genuine.
The stamp has no gum. Scott cat is $3750 or thereabouts. Go to the Specialized 1840-1940 (or Sassone or Michel) and you'll find the no gum price is way lower. My 2003 has mint at $3250, no gum at $1000. The stamp has dirt on the face. Looking at the back, it might have a corner margin crease only in the margin. It is just barely 4 margins, not F-VF to me, but anything can be said about grading. An OG copy with margins like at the bottom but all around plus a Diena certificate would bring about a half of catalog at auction or more. Pricing steeply decreases as quality goes down, particularly for classics. Also see the
ebay bids for this; 38 bids by 20 bidders says the winning bid level is likely correct. Add in that
ebay is a haven for cheap bidders except on the most desirable items in best condition and the sales price make sense.
And 13 negatives in nearly 44,000 sales is bad? I don't think so. You have to read the negatives to see what the problems are; I don't think it's worth my time to do that.