A lot of the comments were from people who paint watercolours themselves. No-one was saying that Turner had better move over, but most thought he used a difficult medium very well. He is, after all, painting as an amateur for his own pleasure and displaying them because there is interest in them. If people want to buy an A G Garrick for their walls, that is their own choice. People pay enormous amounts for things that a pop celeb has just worn for a day.
I have not seen them so will wait to comment until I have something to base an opinion on.
I did not think much of the journalist's approach - and he does not seem to be highly rated either as an art critic or as a practising artist.