The fact that his response rate when from < 5% for "applying the right way" to 22% for "maybe you upset a hiring manager" suggests his new approach, in spite of your reservations, is better for cases where you don't know anyone who can give you a warm introduction to a given company.
If anything, assuming most companies have an 'employee referral' program, emailing a random non-recruiter may have the additional advantage that, for no cost to you, someone at that company becomes incentivized for several thousand dollars to lobby for you.
It's very much a tragedy of the commons scenario, though: if one person emails a random within the company, they're going to stand out, maybe even get put in as a blind referral. If everybody starts doing this, then it's just spam, and the emails are more likely to get dropped on the floor.
This is actually a very good point. Having an incentivized advocate really skews things in your favor and many companies have such programs in place to bring in new hires...
Alternately, it suggests that people getting emails like this should be sure to send them to Recruiting with a "Could not follow instructions, do not hire" note.
If anything, assuming most companies have an 'employee referral' program, emailing a random non-recruiter may have the additional advantage that, for no cost to you, someone at that company becomes incentivized for several thousand dollars to lobby for you.