The Swiss striker went down in the area after a challenge from former Hibs captain Liam Craig, with referee Gavin Duncan pointing to the spot.
Saints manager Tommy Wright suggested the 23-year-old had gone down too easily, but replays showed there had been contact.
However, Davidson took aim at Kamberi’s actions, with Marc McNulty dispatching the spot-kick before going onto grab the winner with a little over five minutes remaining.
Asked if the Hibs forward had dived, the St Johnstone midfielder said: “I think it’s pretty obvious. I have watched it back and I knew at the time but I have to be careful what I say as I might get into trouble. “I knew by his reaction. When I said to him he just kept blowing kisses to me afterwards. If he had been kicked he would have said that. Never once did he say that.
“It’s on the pitch, we’ve all shouted at each other and had stick. That’s not the issue.
“My issue at the time was that he’s done whatever he’s done to win a penalty for his team and he will have sat on the team bus down the road not caring as he’s helped his team get three points.
“That’s the way it is. I’m not getting away from the fact that we should do better at one-each but it’s a big decision at a big time in the game. And I just can’t see how the referee’s given it.”
Admitting that he had to watch what he said for fear of incurring the wrath of the Scottish FA’s compliance officer, Davidson added: “From what I see, he throws himself in, throws himself to the ground. Some people will probably say it’s good striker play but if you are going to give penalties for that, each game will be seven each because there will be ten penalties per game.”
Davidson conceded that it was hard for referees, and accepted that it can take “minimal contact” for a player to go down.
“In the moment you can do that sort of thing instinctively, and certain players do that,” he said. “Sometimes it looks like a dive and stuff when people go down but it can take minimal contact to go down.
“It’s hard for referees. I’ve known players that have dived. People have dived in my team. Everyone in the game has gone down easy at some point or another. I’m frustrated because it was such a big moment in the game.
“As I say, it’s not an excuse because at one-each when they get a man sent off, we should do better ourselves. But I’m frustrated as it changes the whole momentum of the game. At that time they hadn’t created a clear-cut chance. “
Defeat for the Saints consigned them to an eighth game without victory - their longest winless run since February 2016 - and despite an impressive start to the campaign, they now face a fight to overhaul Hibs, who now sit three points ahead of them with a far superior goal difference, for that final top six spot.
Teams, as well as players, can fall easily.