peppa stick with ds, he needs you.
The others are wrong about the correct technique. You are right.
If it helps to understand why they do it, I have this, possibly way-off-the-mark, observation. My dad, when my mum died, constructed in his head a reason (it was all the GP's fault). He is a brilliant, self made man and a scientist. The (new) doctor observed 'it is hard for scientists, because they need a reason. But at the time you think the GP should have done more, there were no treatments for this cancer'
That was over a decade ago, but my dad has gone on adding extra thoughts to his idea that it was the GP's fault.
I think my dh is the same - science degree - he still finds it hard to accept the diagnoses of people in the wider family and that 2 went to special school. Even though one is now grow up, working and married and rates his special school as the sole reason he is not locked in his bedroom depressed and on benefits.
The terminology 'something wrong' really doesn't help. There is nothing wrong with people in a minority accept the failure of the majority to be accepting of widening their techniques to include some minority folk. Us wheelchair users no longer get 'does he take sugar'. Stephen Hawkings has done a lot for us, too.
So remind them that nobel prize winners, and loads of high performers in silicon valley have aspergers, and if they had been crushed by the techniques your dh is suggesting, then we would be struggling without half the features of our PCs, laptops and mobile phones.
So there.
Be i your ds's corner - I am still regretting every moment that I was not in the corner with my dcs.