Every tech company is going to have bad operational issue days. Going at your competitors customers regularly when your competitors have bad days will net you more negative reactions than positive, in my opinion.
Not to say that you shouldn't do your best to make sure your customers are always able to continue business, but like you said, everyone has their bad days. I'd choose to have loyal customers that aren't jumping on social media at the drop of a hat and publicly "chastising" the company.
* Also, "I'd love to speak to you more about the issues you're experiencing" does not mean "offer to help fix the problem" as he mentioned. Unless he means, leave his current provider to move to them.
The key here would be unsolicited (yes) and bulk (possibly no). It is impossible to tell based on the blog post, but I find it less likely that there was a bot designed to find customers after a rival outage than a human doing it. If there was a bot however, that would be spam.
I think many people on here would agree that it is annoying and would probably be ignored or marked as spam, but I don't think it is spam.
It is definitely spam in other countries, though, where the criteria is unsolicited.
The flaw in this definition is that the recipient has no way to tell whether a message was sent in bulk or not. After all, if spammers have a database with your address in it, they can have your name as well, or they can guess it from the email address and thus personalize the email you receive. And if the recipient can't tell whether a message was sent in bulk or not, then guilt can't be easily established, requiring a costly investigation from competent authorities.
The problem with email is that it's very cheap to send, much cheaper than making phone calls and the problem with spam is that if unaddressed, it renders your email address unusable, with important, legitimate email being lost in noise, so it does have a high cost for recipients. And that cost for recipients is the same, whether those emails where sent in bulk or not.
So you see, such a rule is designed to protect spammers, to shield them from legal liability.