Whereas, the middle-class are hurt by inflation since they must spend more their income, and they are hurt by deflation, because their wages decline.
How do declining wages hurt if prices of goods equally decline?
Once you have that cartel, you can eliminate those outside the cartel by delaying their transactions or charging transaction fees only to your competitors (billing the competitor, not deducting from the payer in the system).
Not only do I debate the author's theory on how cartels could form, but how can you discriminate against anonymous public addresses? Even if you knew IPs, the transaction could just be relayed by someone else.