Xhaka is currently serving a four-match ban after being given his marching orders in last week's 2-1 win over Burnley, his ninth red card for club and country since 2014.
To exacerbate the situation, the Swiss international was at the centre of a race row when he and a friend argued with an employee of British Airways over the checking-in procedure of a flight.
Xhaka wasn't taken into custody, but did visit a local police station for a statement when the alleged incident was reported.
Wenger, though, doesn't feel Xhaka should be singled out for abuse.
"There are two incidents which have been talked about," Wenger is quoted as saying by AFP.
"One is the sending-off. I felt that the sending-off was harsh when I watched it again. It was not a dangerous tackle, it was a clumsy tackle.
"You have to accept that he can be punished for these kinds of tackles now. He has to learn from that. I don't think he wanted to injure anybody.
"He has to learn from it. Unfortunately we will lose him for four games in a very important period of the season.
"The other incident, at Heathrow, he denies completely. I have talked with him about it and he completely denies what happened there.
"I can only talk about him on what I've seen since the start. He's had a fantastic attitude since he arrived here on a daily basis.
"Sometimes you don't know how the players will behave on a daily basis but I must say that he has been absolutely marvellous to handle with his commitment, focus, dedication and I've never heard anything bad said about him."