sorry if I'm a bit slow but I don't get it.
if a 38% miner spends fees that he gets back, how does that help him?
and how does it hurt other miners ? if anything it would seem that the other
miners would pick up extra fees, making them more competitive, not less.
someone please explain this.
You have answered your own confusion with the bolded part. The one that would pick up "more" miners fee will be the one that owns more hashing power. The miners fee will be increasing because people will want their transaction to get confirmed faster if there is someone spamming the network thus this means that if the spammer is a person behind who owns atleast 38 % of the hashing power then this person will get profit with the increasing fee ( this would be somewhat a miners fee cartel )
Let's work the math. If 2/3 of the transactions actually processed are "real", then whoever is maintaining the backlog is paying the tx fees for 1/3 of every block. If this is someone with half the mining power then they get half of their third back, so their average cost per block is the fees for 1/6 of the block. If we are talking about someone with half the mining power, their average return per block is 1/2 the fees for a block. Because 1/2 is greater than 1/3, they are making a profit.
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It is not in their best interests to add bogus transactions to the queue because with a smaller fraction than 38% of the mining power they would lose money on the fees they invest.
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Miners for whom this is profitable must control at least 38% of the mining power. Therefore there can be no more than two miners doing it at a profit.