The autism thing is hardly the most outrageous comment to make. Neurodoversity is something the world is only really starting to recognise and explore now, there will be numerous generations never diagnosed because there was little to no understanding when they were in their formative years. We can all see that John is socially awkward with being interviewed and we've seen him react to criticism, its not a massive reach to say he is fixated on this sport.
I don't believe for one second the poster is blaming this decision on John McGlynn being on the spectrum rather just raising a point as to why he may struggle at this time to fully comprehend everyone's reaction to to the signing.