I think we need to put this in to some sort of perspective.
Paul Nicholls has absolutely no obligation whatsoever to allow anybody to come and look round his yard. He is very open with the media and we get a lot of 'access' to his yard, whether that be through his Betfair column, gallops videos, and so on. It is simply not possible to have people continually coming to look round the place and as he says, their facilities do not allow an open day type event.
It must be remembered that trainers of the calibre of Nicholls/Henderson are about the busiest people in the country, literally flat out from 7 in the morning until 7 or even 8 at night. They have a business to run and cannot spend time accommodating people who want to come and pat Kauto Star on the nose for free. Moreover, a busy racing yard is simply not a place suitable for people without the necessary acumen to avoid the flying hooves, bucking horses, etc.
Obviously Paul does not have the time to sort out these people on his own so in order to allow people the chance to come to the yard he must hire somebody to run the tour operation. That incurs a cost, and means that the consumer must pay for the service. The very fact that the "£95 per person" tours "are completely sold out for 2012" suggest that it is actually a very fair price indeed.
Of course Nicholls is making money from it but if you had worked as hard as he had to get where he is, you had the best stable in the land, featuring Kauto Star, the 2nd greatest horse of all time, Big Buck's, the greatest staying hurdler of all time, Denman, general legend, and so on, would you not do the same?
I find it hard to understand the criticism. My only criticism would be as an economist - Why is he not charging more if there is a supply shortage?!