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The current problem with block size is about bytes and spamming is about generating lots of transactions or transactions with very big reprsentation (in bytes). This title refers to blocksize in bitcoins sent.
I think, sending large number of bitcoins in a transaction and sending several minute amounts of transaction is same is the final block size exceeds the appreciable limit.
Moreover he was constantly trying to limit the confirmation speed by sending in his own addresses many times.
This may also decrease the value of Bitcoin Days Destroyed!