A number of supporters chanted 'Bruce must go' towards the end of the 1-0 home defeat against Norwich on Tuesday night and the team were booed off the pitch at the end of the game.
"A few weeks ago, we were top of the league and it still wasn't good enough," Bruce told the Birmingham Mail.
"People, the doubters, need reminding. This club was nowhere nearly five years ago. It had not been in the top division for 16 years.
"It's in my nature to have a go and show people, and that's what I will do. It's the way football is now, all this criticism. It's total, utter nonsense.
"What club benefits from it, making a change? Maybe for two or three weeks.
"People say 'West Brom' but they've got Kamara back, Davies back now. I heard someone on the radio the other day say that 'the shackles are off' after Bryan Robson left.
"What rubbish. Everything is short-termism."