Why? Because you can't be bothered to.
You would rather give him a black mark on his account with the knowledge that only 3 in his life time would get him permanently banned.
I don't like that Google banned this guy from Google wallet and from buying apps, but I have no issue with them banning him from publishing new apps. He blatantly violated trademarks repeatedly, and he published low-quality apps that by his own admission were identical except for an ID change, and provided no functionality aside from being a YouTube wrapper. He's a spammer.
Why? Because you can't be bothered to
Yes, because it's a waste of time and resources.
One developer, one email conversation, fine, not the largest time investment.
What about all of the other developers in the world?
Especially if this became a recognised method of gaining work?
Suddenly you need full-time staff dedicated to the non-core-business activity of writing "gentlemanly" emails.
It's unworkable.
I would gladly pay for Google support, and I've stated as much in the past.
I have paid for Microsoft support, and it was a great experience. Microsoft is (or was) as big or bigger than Google, and used by a significant fraction of the population.
So, it can be done. Google doesn't want to do it.
I agree that the original content owners shouldn't have to contact the creators (it would be nice though, most are way too overzealous).
Noone is really entitled to free handholding from others in the first place, and doing harmful stuff (such as spamming the appmarket with those fake apps) doesn't offer any extra rights, it can only offer extra duties.
It would be harsh to punish someone after the first offense, but if someone is showing both with his words (the "clarification" sent to google) and actions (the other two strikes) that he perceives those actions as socially acceptable, then there's no duty for anyone to reeducate him when just putting him on lifetime ignorelist achieves the required result (protecting appstore customers from such publishers) much cheaper, faster and better.
So it's not really impersonation is it?
Plus they can always just request nicely for it to be removed if their really that bothered by it.
What is with this need of taking drastic measures for something as simple as this. Whatever happened to talking to the developer and sorting it out like gentlemen.