I'm not planning to move anywhere tbh.
Mozilla is almost 100% financially dependent on Google right now, if that funding goes away then so will Firefox, the Gecko engine, and likely all the forks. With all the layoffs happening in the industry, we can't rule out Google shareholders looking elsewhere to cut costs too, such as the massive subsidization of Mozilla. The little we can do is allow Mozilla to find other sources of funding that are optional for users IMO
Yes, stuff like pocket is garbage. But at least Mozilla allow you to turn it off, which is more than can be said for Google: on Android devices manufacturers have to pay a hefty "fee" just to allow users to remove the Google search bar from the launcher. As a user you can get around this by installing a custom launcher, but as a manufacturer, you will not get Google certification: no SafetyNet (Play Integrity DRM, required by Banking apps), no Widevine, and Google will block GMS & their other apps on your product.
Regarding AI, mozilla's memorycache is completely local (runs on the user's machine) and does not call out to any servers. The new translation feature is the same. The only exception to this that I'm aware of is the AI helper on MDN, but the target audience of that site is already in a position to determine whether that is a useful feature or not.
That's pretty unfortunate for the blog author, can imagine making that kind of mistake early in the morning will really wake you up.
The blog doesn't mention specifically whether the author had uploaded using a Lemmy app or the webui AFAICT - if he used an app, there are some that actually store the auth/delete token returned by image uploads, and provide a section within the app where you can manage/delete (purge) images you've previously uploaded to Lemmy