No it isn't. That's a ridiculous blanket statement. Every child is different.
My youngest (now 14) autistic/learning disabled/ADHD impulsive profile) has had age appropriate access to an iPad since he was 5 - We set careful limits on content/apps/etc. All devices downstairs overnight and not after dinner but have never limited his usage outside of this.
The result seems to be that he uses it when he needs it and his usage changes depending on his regulation needs (eg will watch train announcements when he feels overloaded or old Peppa pig episodes) and looks for new content when he is interested in something. Or logs into his school accounts to catch up on some maths or English.
We have had no arguments over his usage at all (and he is now 14) - he will happily put it down to join in a family game, go for a walk, empty the dishwasher or engage in a creative activity) - he puts it down when he's had enough and heads off to find something else to do - or asks someone in the house to engage with him for something else - his access to his iPad has only ever been a positive thing for him.
He uses it to take photographs, to take videos of himself practising role play dialogues, to play with Google maps and street view and explore the world, to plan imaginary journeys or find out about trains all over the world. To watch videos of kids doing kid things (the ethics of that is a whole other discussion though) - sometimes he will flick through shorts quickly, other times he will watch the same video multiple times and can recite pretty much all the local train announcements.
He can access music and a wide range of audio books whenever he wants (given his reading skills are still developing this has been vital in terms of developing his literacy - literacy being a wide range of storytelling mediums not just the reading type which is a very myopic version of true literacy
It has given his access to 'social currency' in the form of train information to bond with peers and also wider cultural trends eg kpop demon hunters - which gives him a point to connect with others away from the screen. He has learned the foundations for basic coding, how to plan journeys across London, make a photo book with Canva, digitally manipulate photographs and even basic password management.
We have recently given him limited access to a mobile phone to teach him how to use it - again with strict parental controls on times - and after an initial period of over indulgence - he has settled into a pattern where he self regulated his usage and the checking of messages etc.
His use of 'screens' has only ever been a positive for him