This is a great scene! If you haven't seen the John Adams film then you really need to. The following comes from The American Catholic Site:
America has been blessed by God in many ways but perhaps no blessing has been greater than His granting us George Washington to lead us in our struggle for independence and to be our first President. Catholics have perhaps more reason than other Americans to keep the memory of Washington alive in our hearts. In a time of strong prejudice against Catholics in many parts of the colonies he was free from religious bigotry as he demonstrated on November 5, 1775 when he banned the anti-Catholic Guy Fawkes celebrations.
“As the Commander in Chief has been apprized of a design form’d for the observance of that ridiculous and childish custom of burning the Effigy of the pope – He cannot help expressing his surprise that there should be Officers and Soldiers in this army so void of common sense, as not to see the impropriety of such a step at this Juncture; at a Time when we are solliciting, and have really obtain’d, the friendship and alliance of the people of Canada, whom we ought to consider as Brethren embarked in the same Cause. The defence of the general Liberty of America: At such a juncture, and in such Circumstances, to be insulting their Religion, is so monstrous, as not to be suffered or excused; indeed instead of offering the most remote insult, it is our duty to address public thanks to these our Brethren, as to them we are so much indebted for every late happy Success over the common Enemy in Canada.”
Order in Quarters, November 5, 1775
– George Washington
This stand against anti-Catholicism was not unusual for Washington. Throughout his life Washington had Catholic friends, including John Carroll, the first Catholic bishop in the US. He would sometimes attend Mass, as he did during the Constitutional Convention when he led a delegation of the Convention to attend Mass in Philadelphia as he had attended Protestant churches in that town during the Covention. This sent a powerful signal that under the Constitution Catholics would be just as good Americans as Protestant Americans.