As I reflected later I thought, "Well yeah, they're trying to protest", but ultimately what a Catholic is doing, or any person who walks out of church while the priest delivers remarks, is an attempt to use intimidating behavior to dissuade the priest from preaching the truth.
In their own reflection they may say, "I don't wanna hear this" but what they are ultimately doing is withholding their presence from the priest in an attempt to intimidate him, force him to choose between them and God.
I won't hesitate for a minute to choose God over any other human being, and no other Catholic should ever hesitate to do the same. This is the very sword of which the Lord speaks when He says parents, inlaws, families, will be divided as a result of His teaching.
And the greatest tragedy of all is that the Catholic who walks out of ongoing Mass, except in emergency, is dividing himself from Christ.