McCarthy claimed his players were upset because they felt Scharner had lifted his match shirt and displayed the contents of a T-shirt towards some of them during the latter stages of the Premier League match.
Wolves substitute Stephen Hunt appeared to be angered by Scharner's actions and was involved in an exchange with the Austrian.
But Scharner defended his actions, insisting the T-shirt only contained a club logo and the words 'West Bromwich Albion', and was aimed at the Baggies supporters.
McCarthy said: "Scharner had something on his T-shirt and showed it to the lads over the other side (of the pitch).
"There is no need for it and maybe that upset the lads. You can lose but you don't need your nose rubbing in it.
"If there were words said (between the players), it would have been because of that. He lifted up his shirt, there is no need for it.
"It's when you get responses. Take the mickey with the ball, that's the game. I get the hump with it."
But Scharner is adamant his actions were not meant to anger the Wolves players.
He said: "My kids gave me the T-shirt. They stuck a club logo on it and I was just showing it to the fans. That's all."