I think Patrick picked the numbers quite intentionally and in light of that the comparison to spam doesn't hold water. Bob is said to be the 1 annoyed user out of 100. In other words, 99% of people are finding the emails useful. That's the argument at least.
Spam, on the other hand, is far to the other extreme. Way more than 99% of recipients don't find those emails useful (not to mention they were unsolicited emails).
It's a hypothetical argument involving a fictional corporation. The numbers are made up.
I think Patrick is saying that, assuming most people are satisfied, it's acceptable and not at all evil if a small minority who signed up for the emails in the first place turn out to be annoyed.
Spam, on the other hand, is far to the other extreme. Way more than 99% of recipients don't find those emails useful (not to mention they were unsolicited emails).
e.g. "After 26 days, and almost 350 million e-mail messages, only 28 sales resulted" https://en.wikipedia.org/wiki/Spam_(electronic)#Cost-benefit...