I can see the issue with spam-bots, regardless of the self-nuking, and how especially this community is targeted. But I wouldn't consider the accounts marked in this post as spam-bots at all.
If this community or instance considers a couple of posts a day, perhaps specifically from new users, spamming, then as a user I'd expect that rule to be written before actions are taken.
In general, I'm not disputing the actions of the mods and I hate to be the guy who expects something from people who contribute to this platform in their free-time, but for these kind of bans based on suspicions and patterns, I just wish there would at least be more transparent communication.