This guy over the years has spewed constant bile towards the club and is currently doing the same alongside his side-kick the awful Ian McGarry. The below article from 2015 sheds some light on why he might be so hostile towards the club.
"Archival data released for the first time this week has revealed that football journalist Duncan Castles was repeatedly rejected as a member of the Manchester United fan club as a child.
The data’s release, prompted by Manchester United fans eager to know the inner workings of their club, inadvertently revealed that the writer for the Sunday Times was rejected on a record 68 occasions after applying for membership of the team’s fan club, between the ages of seven and 13.
Speaking today, a member of the club’s administrative staff explained the details behind the rejections".
“We didn’t even realise we’d rejected the guy to be honest,” said the source. “Our data tells us that the first 12 rejections were simply administrative errors.”
As time passed however, the source added, Castles’ applications became more and more threatening in their tone.
“After we finally noticed our error it was sadly too late. This child had lost his innocence. By the end the letters were just pages soaked in blood.”
The club’s revelation may go some way to explaining Castles’ attitude towards the club in his writings, said the source, adding that there was surprise among staff in the fact he’d become a journalist at all.
“It’s good for him I suppose, that he’s got a major outlet for his large amount of anger. But given that most of his articles, like his letters, are just angry bile it is peculiar to say the least.”
Despite apologising for the error, at press time the club expressed relief that it kept “such a dangerous and strange man” away from the club".
https://www.tbnsport.com/2015/10/04/duncan-castles-repeatedly-rejected-by-man-utd-fan-club-as-child-archives-reveal/