There are people that don't believe in evolution, and people who believe their religion forbids them from taking modern medicine. Why is this that shocking? We have proof that contradicts a lot of popular beliefs, but people continue to latch on.
I mean, I was pretty shocked that people were as... extreme as they turned out to be when I learned about it the first time to be fair. I didn't know about the aluminum-foil-hat style chemtrail poison-is-everywhere-how-are-we-not-all-dead-yet types until pretty recently in my life. In fact, until I started researching evidence based nutrition after I tried a fad-diet and got real sick feeling (worst month of my life) around the same time gluten-free-ism became popular (I never tried gluten free though), I really didn't have any clue how uneducated people were--or unwilling they were to be educated in stuff like this.
But really, everything is so damn shocking about this. How joking it really sounds aside.. the EVERYTHING is just straight up bat-shit.
That paleontologists are somehow millionaire assholes that aren't working hard long days of thankless passionate work to never be recognized except through a small following for things they made happen like everyone experiencing the magnitude of dinosaurs at their leisure for $20 max.
Or how somehow the whole globe who cannot unite on literally anything just about since Hitler died just got on board and said "Yup!" to promoting evolution.
Or how all of the expensive equipment, time, care, and pain staking measures are taken to preserve something that we supposedly made out of Spackle and some pinterest photos.
Or how just... flabbergasting the video that girl posted is. Everything about it, from how you can tangibly feel how illogically her brain processes things and how she jumps from topic to topic in such a haphazard way, to the subject itself not even being well expounded on.. Just loose-change style "I know I'm right, I'm telling you I am, now you should believe me" that I haven't seen since... Well.. Loose Change.
And, probably most importantly, is how crazy the number of followers they have is. It is a ridiculous amount. Not hundreds. Thousands of people. And sure, many might just be trolls or people observing for the sake of it.. but they aren't all trolls. A good majority is probably genuinely interested.

If that all represented in a 5 minute video isn't shocking, I dunno what to tell ya. I was definitely shocked by it. Not completely surprised because, as you said, people believe a LOT of horseshit.. but it is not the normal "Girls cannot eat more than 1200 calories because then no one will marry you" bullshit for sure.