To be fair, he does. Fog Creek has been going for over 15 years. Trello started with a similar model - only free use at the start as they figured out the best way to monetize, and now they are making $10M+ a year [1]

1 - http://www.forbes.com/sites/alexkonrad/2016/05/23/trello-get...

Worse than not making economic sense, it opens the door wide for malicious users - I'm sure some guy is already working on setting up JS-based bitcoin miners that just use up these free, no-login servers' CPU capacity, or set up malware sites, child porn hosting, you name it.

The barriers - login, mainly - aren't there to annoy users.