A constructive comment would have been to point us at good spam filters that are very good at not allowing obvious spam so that we do not make the same mistake that Twitter did and be labelled as "idiots" by the likes of you on the Internet.
Seriously, this problem is not as easy to solve for machines as you think it is.
And email seems like a harder place to police, being decentralized. These guys control the gateway to the service!
The first rule is you don't delete user data without consent. The second rule, is you dont delete user data without consent!
And yes, I work in the industry. Bad shit happens, and data can be lost. But trusting some automated 'spam detection algo' and making actionable, irrecoverable decisions on fuzzy math is completely idiotic, boneheaded, and fucking stupid! If you're in that product team, you deserve every shred of scorn you're getting.
I think some of the reason this comes about is that it's deprioritized until it's a major problem, and you're already at a large scale, and then the decision is "require human review, even of what appears to be a fraction of the deletions, and get swamped with thousands or tends of thousands of reviews immediately", or "just delete them".
That's not an excuse for the decision, since obviously they could have taken care to address this problem at least minimally much earlier, and there wouldn't be a deluge of work, but I think we all understand whey they weren't keen to do that (even if it's a crap decision for their users).