This is true, but I am a SEND parent and my take on it is that screens are a tool and like any tool they can be misused.
We don't restrict screen time in our house.
I used to have really bad PFB syndrome with DS, who was non-speaking, and at our early SALT appointments it seemed like he may never speak, he never copied noises or showed an interest even when we were being child led. I had a no screen policy. We talked all day at him, we narrated what we were doing, we copied his vocalisations to see if we can get him to eventually copy ours. Our throats were hoarse at the end of every day. I often said it felt like we'd used up our allocated word limit for the day, and still felt like we were failing because he wasn't speaking.
One day I came home from work and DP had put on this YouTube video that was loud and overstimulating to say the least but DS was singing and signing the alphabet.
I asked on reddit for less overstimulating content, and we moved to Yakka Dee and the Twirlywoos, but didn't abandon intensive interaction based play or books, and it just became an additional resource.
Now DS is speaking, but significantly delayed still, and sometimes he comes home from school absolutely wired, to the point he will hurt himself or others accidentally. No amount of running him round, rough housing, parks, trampolines, ball games etc would tire him out, but some old 90s and 00s style cartoons would get him to sit down and drink and eat a meal where he would otherwise not, and was losing weight rapidly. There were days where we would limit or restrict screen time completely, and he would only have had a few sips of a drink and a nibble of something to eat.
Understimulation can be just as bad as overstimulation and I think unless you've experienced this with your children then it's a hard concept to grasp as a lot of focus is about how overstimulating today's media really is, but for sensory seeking children it can be an absolute lifesaver when nothing else is working.
These days DS likes to replay short clips on YouTube as a means to regulate, and they are categorically overstimulating clips, but the repetition fulfills the need of needing to know what comes next, familiarity and routine when the rest of the day has been unpredictable and overwhelming; when the day at school hasn't gone quite to plan, or when visitors pop over unannounced on the wrong day of the week, or when there's a transitional period like school to school holidays.
Guidance is good, it raises awareness, but there's no one size fits all model for children, and screens should not be the only tool in a parents arsenal. I don't think guidance alone about screentime is going to be effective, there needs to be support in recognising children's needs and behaviour alongside it.