This is NOT something trivial. This goes to the heart of showing Our Lord and God respect during the Holy Sacrifice of the Mass, the most sacred action in the entire world.
Let’s say you had committed a horrible, horrible crime, too horrible to be mentioned. Then, when it appeared you were about to be condemned, the President (or King, or whoever) decided not only to parden you, but also to adopt you as his son, and shower you with righeousness, show you what the right way is to live. In addition, this President is giving you his entire estate. You will be set for life, you will be awarded more glory and honor than you ever thought possible.
Now, imagine that the time comes for you to thank this President for turning your life around, for giving you a second chance. You go in, and start chewing gum, acting distracted, and don’t even seem to care what is going on. Would that be right?
Well, that is EXACTLY the attitude of someone who chews gum at mass. Our Lord has set us free, through His Passion, Death and Ressurection. He has made us ADOPTED CHILDREN OF THE FATHER, PARTAKERS IN THE DIVINE NATURE. And we DARE to chew gum at mass?
The argument that this is trivial, that there are more important things in the world, reflects the typcial socialist-liberal-secularist outlook on religion: it’s sole function is to help the poor and fight violence. While this is certainly important, it does not end there. Catholicism is about HONORING THE TRIUNE GOD, and it is exactly comments saying that chewing gum is “trivial” that reflect the attempts to secularize the Truth.
God will not be mocked.