My impression was that a lot of the content was effectively "attention slop", bright colors and noises, often with very little sense to them, or just variations of the same rhymes a 90's baby would've been raised on.

A lot of it seemed to cross over from just being stimulating to being overstimulating.

At 2 kids can walk and have fine enough motor skills to press a small button, if that was the direction you were thinking.

Kids are surprisingly intuitive and form connections super quickly. It probably took a few tries, and maybe the parent even showed them how to do it: button appeared in the corner > press it > see fun content. If something works they commit it to memory like you wouldn't imagine.

He goes to swimming classes and he learned to clap in the "If You're Happy and you know it" song even though the song is different in his classes, I was confused as to how he learned that you usually clap in the song but I presume he learned it from Ms Rachel.

It's useful English language exposure for him too as we live in a non-English speaking country and my partner doesn't speak English either so without TV I am his only exposure to English.

I wouldn't let him watch it for 8 hours, but I presume that's the typical newspaper sensationalising.

At 2 years old?

There are babies under a year who watch youtube brainrot shat out by obscure indian animation farms multiple hours a day, I'm not sure it has the same impact as watching Stargate when you're eight. My niece is 9 months, she never watched anything on a phone yet as soon as someone in her line of sight gets a phone out she's mesmerized, it's scary to witness

That is likely the key element, along with being the reason why the guidance suggests no screen time before the age of 2.

Some parents know what their child needs, some parents don't know how to navigate the mess of children's content, some parents would use it to justify using the screen as a babysitter. It is nearly impossible to offer generic advice, so it tends to be on the safe-side.

It is also worth noting that you are using one metric here, assessments based upon academic achievement. There are other things to consider, such as social and physical development. Perhaps your family is also taking that into account, but again they have to consider how everyone would interpret generic guidance.

But there’s a reason the AAP recommends no screen time before 2.

There’s a lot of data that show that babies and toddlers don’t learn language skills from TV for some reason. And it inhibits learning because instead of doing what they’d normally do which is watch and listen to adults and older kids speaking they are glued to the screen.

When he is at a party and a tv is on in the distance he stares like a zombie at it. It's depressing at how TV changes him and I have to transfer his focus away.

Seeing all the kids my kids play with, the ones who seem to turn out the most well rounded aren’t the ones without screen time but the ones without helicopter parents.

You’d be surprised how many of these kids have never been outside of their parents line of sight, even at middle school age.