Celtic traditionally draws fans from Catholic communities in Scotland and Ireland.
The match followed hours after Scottish nationalist politicians published proposals ahead of an independence referendum next year.
Lawell sees the UEFA charge as damaging for the club's reputation.
"Our supporters do not want this anymore," he said. "We are a non-political organization, a top football club in fantastic shape, aiming to play its part as a major football club on the European stage.
"Regardless of the political views people hold, football stadia, whether it is Celtic Park or anywhere else, should not be used to promote these. This is something which all football authorities, including UEFA, have stressed for some time and something well known by all supporters."