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.
Coincidentally or not, you've just explained why spammers spam. Not that I disagree with you.