The Ghana international said the knock-on effect was obvious in training the day before Portsmouth's visit to St Andrew's.
"I can't say it didn't affect us because, on Friday, training wasn't like it was, it was a little bit slow, slow, slow," he said. "We didn't fight, normally on Fridays, before a game, when we are playing you can see more fire, but it wasn't like that. I think it has affected everyone.
"Hopefully the next game everyone will come together and it will be like it was."
Kingson, who returned from international duty on Thursday evening and detected a mood change the next day at Wast Hills, continued: "I was so sad that the coach left.
"I found out when I was in Ghana and the press were asking me about it.
"All I can say is that it's football. We have to put this aside and concentrate on what is ahead. For any coach or anybody who is going to lead us for the next game we have to show the same respect we did to Steve Bruce."