The author is just interpreting effective email copy as aggressive communication. Good copywriting persuades the user into doing some action. But When you have no intention of doing that action, the persuasion, or pressure, that the copy induces by trying to make you do something that you don't want to naturally seems aggressive.
I'm not trying to justify the amount of emails that Weebly sends. That's way too many and way too annoying. But lets face it, the content of those emails is simply effective copywriting and the author doesn't like how it makes him feel.
Well, by his admission, he was using the account to help edit someone else's site with the service. I think that places him either as someone who is no longer a prospective user, or a type of user that falls outside their retention and engagement processes. In either case, that doesn't really negate the GP comment's point.
I'm not trying to justify the amount of emails that Weebly sends. That's way too many and way too annoying. But lets face it, the content of those emails is simply effective copywriting and the author doesn't like how it makes him feel.