Vimm's been around for 3 decades; I literally visited it within the last 2+ years to browse PS libraries after not touching the website for ~15-20 years, and was impressed that Nintendo ROMs were still up.

This is in no way comparable to Yuzu (modern system) nor the occasional fan initiative to remake an old title with modern graphics or similar creative liberties. Timing is definitely curious.

I have my doubts about the social media theory, but it's not impossible. More inclined to think it's something more mundane like:

• Cleanup is normally performed by 3rd party contractors and Nintendo switched to one that's more diligent about retro gaming, or
• Some executive reaction to newer data / interpretation about the profitability of their Nintendo Switch Online crap that bundles access to retro emulators and games, renewing anti-(retro) competition measures.