using a client that could see and vote in the poll in the 8 minutes that they had it open
The irony being that the ones upset by the API changes wouldn't be using the first party client, so if anything this would have filtered out the people in favor of closing down. I say "would have" because that would require this having actually being what happened. All of those polls I saw were open for days, and the people whining about the closures in the comments just didn't notice because they didn't actually use the site much or were just oblivious as shit.
Common Vulnerabilities and Exposures, it's a system for cataloging security issues. For instance, the vulnerability in Plex that caused the leak in the link above was CVE-2020-5741.
When I called the version of Plex out-of-date, it's because it had an unpatched security vulnerability. Because you called Soulseek out of date, I'm asking you which vulnerability makes you say that.