The Foxes lost 2-0 at Selhurst Park.
"The manager has said a few things but it is just one game and we have to move on from it, and work hard this week," said Simpson to the Leicester Mercury.
"He is good because he makes his point. He said we deserve to know the things you might do wrong and it is a very open dressing room.
"Everyone is together and you have to be able to hear the negatives as well as the positives.
"As long as everyone is comfortable with that it makes the team grow, improve and get better.
"We are new to the Premier League and it can't be all highs.
"There will be some lows and as long as we learn from it then it is positive for everyone."
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