You're over-thinking it, it seems to me.

The video itself showcases quite well a bit part of this: this is a super-duper opportunity to virtue signal at the top of their lungs. This is causing them to nearly tilt over looking for fainting couches, they are getting so excited about all of the Likes coming their way.

Yeah, I know. Sigh. I don't understand it either.

And the second reason is, they think they are going to get these shots and then just like Alice they will be back to original size. Back to their "normal" (weird) life. Except... they are in for an unhappy surprise on that one, when it turns out that that is not going to happen.

Never fear though. When they realize that, they will adopt their next new (spoonfed-to-them) idea: I can't have my pre-COVID lifestyle back because of MAGAts (which is already a narrative well underway).