It is an inflamatory meme. It's simplistic and dismissive. There are deeper discussions to be had about diagnosis, support, parenting and societal expectations but that's not what Jo Frost has tried to do. She presents herself as a parenting/ behaviour guru and this is abusing her position
When a child (or adult) is diagnosed with neurodiverse conditions it's recognising lifelong impairment of "normal" function. I didn't get my child diagnosed because he was "naughty", it was because he was showing long term struggles and delays in co-ordination, excecutive function, sensory inputs, and a "fizzy bottle" child who was great all day at school then would see me and all the repressed emotions and self-restraint would explode out of him. Traditional boundaries and consequences would inflame the situation. Things improved when I adjusted my approach to a more ND approach even prior to diagnosis. What diagnosis provides is an understanding of his differences and facilitating accommodations that help him manage in the world. It's not easy. Things don't jump into place, but that diagnosis helps DS and others in his life to understand his place in the world. It's the same as my other child's label diagnosis of asthma. It's not normally an issue, but that diagnosis gives support (medication) and a plan of how to recognise and treat a flare-up.
There are families that will use anything as an excuse. There are also many families where (undiagnosed) ND is culturally normal and facing up to a child being ND raises uncomfortable questions about wider family life and it's very common for families to resist diagnostic pathways often because of outdated predjudices such as the ones that Jo Frost is propagating here, and people suffer for that because the roots of issues are not explored and managed well.
Modern life has also become less accessible for many neurodiverse people; it's fast paced, loud, stimulating, needs a lot of exective function, social expectation to be professional, literacy skill etc. There are many thousands of ND people whose traits would have been more managable in previous generations. That doesn't mean all was hunkydory in the past, it wasn't, but Neurodiversity is more visible in society because of inclusion policies, and because some "higher functioning" people face pressures that previous generations didn't. Just because it wasn't so obvious, it didn't mean it didn't exist.