Flynn, 28, had his contract terminated at the Galpharm Stadium on Tuesday night after failing to impress Lee Clark, having been signed by previous manager Stan Ternent last summer.
And he told the Bantams' official website: "It was very frustrating. I was top scorer at the start of the season, but when Stan got sacked I was told I wouldn't play.
"I'm always loyal and I don't think 15-16 games is long enough for any manager. While I was out on loan, Lee Clark came in and I was fighting a losing battle straight away.
"He wanted his own players just like Stan did and that's the way football works. I had to get my head round that, but things change."