Nobody cared at all

The mods cared. There were many bots used by moderators that relied on karma, the main one being automoderator.

Of all the formats you mentioned these are supported on popular platforms:

• Twitter: gif
• Discord: gif
• Mastodon: gif
• Reddit: gif, apng
• Tumblr: gif, webp
• Lemmy: gif, apng, webp

That’s why gifs are still a thing.

The fact that GIF is still a thing in 2023 is baffling

As opposed to what widely supported animated image format?

Your link talks about the element zapper, the icon that looks like a lightning. The instructions above talk about the element picker, the icon that looks like an eye dropper.