I agree with their petition for basic signing skills to be taught in schools. It's easier for a hearing NT person to learn to sign than it is for Deaf or communication disabled people to learn to speak, and it'd make society more inclusive. (And even though Makaton isn't aimed at Deaf people, it sounds like it's similar enough to BSL, which is meant for Deaf people, that skills would likely carry over a lot.)
Plus, there's benefits to signing even if you can speak well - for example, how many people have been frustrated at a dentist's office because they want to tell the dentist something while the dentist's hands and equipment are in their mouth? I know teaching my parents to understand some basic ASL/PSE signs and translate for me has made dental visits a lot more comfortable for me.
And a lot of programs for dyslexia use hand gestures as sound cues for phonics practice. If they used fingerspelling instead of gestures made up specifically for that educational program, they'd get the same educational benefits but also give the children a communication tool they can use in the future.