Counterpoint is that Mailgun likely had flagged the account (80% deliverability is bad) and wanted to open a line of communication without coming across as hostile. It wasn't a sales opportunity, it was a "you need to improve" email wrapped in a friendly opening.
Evan then replied taking a hostile footing, which resulted in the sale rep backing up his opening with a list of agenda items (list cleaning, dedicated IP address, etc).
At this point it became a purely defensive line-by-line encounter because egos got involved once the Mailgun rep listed the real reasons he was writing.
IMO this is a massive overreaction and not a good look for the blog author.
Evan then replied taking a hostile footing, which resulted in the sale rep backing up his opening with a list of agenda items (list cleaning, dedicated IP address, etc).
At this point it became a purely defensive line-by-line encounter because egos got involved once the Mailgun rep listed the real reasons he was writing.
IMO this is a massive overreaction and not a good look for the blog author.