Ouch. Well, you can go to the Catechism of the Catholic Church to find that missing Mass is a grave offense. Of course, you will also find that missing Mass due to illness, need to care for sick or young children/infant, lack of transportion/major hardship are not grave offenses.
Couple this with both poor catechesis (on the part of both teachers/students, clergy/laity alike) and you will find people quite honestly convinced that an ache or pain, or a minor inconvenience, or a scheduling difference, is a legitimate reason to miss Mass. Considering how few people appear according to statistics to understand that the Mass contains the sacrifice of Christ and His Real Presence, but instead equate it with a ‘community gathering’, it isn’t surprising that the same people who will miss work for the above ‘minor or personal reasons’ would consider Mass on a par with work and equally ‘skippable’.
But how to address this? There most certainly are sufficient reasons for one to be obliged to miss Mass, and people are different. A person with agoraphobia might be physically capable of attending but not emotionally so. One mother of an infant with a large support system might be perfectly willing and able to attend Mass with her infant; another mother of an infant might be a single parent with no support system, and not be able to attend Mass with HER infant. One man might have ‘minor’ aches and pains but they’re on top of a chronic illness and thus his health is very different from the man of robust physical health who just the night before may have exerted himself more than usual; the former and latter may have exactly the same pain in exactly the same muscle but one might really not to be able to go whereas the other could. . .
I don’t want to be the judgment police, not even for those near and dear to me (though that may be something I’d be called on to witness to, with great caution and charity), and certainly not for somebody whose health history and other factors are completely unknown to me.
Of course, the biggest problem is what people “think” they know as opposed to what really “is”. Most of us would be rich if we had a dime for every time somebody told us that “the priest”, “the bishop”, “the DRE”, or “the Church” says that it is “okay” to do everything from miss Mass, go to communion while in mortal sin, engage in premarital sex, have an abortion, support abortion, disbelieve in Church teachings, etc. etc. For those cases where it IS the priest, bishop, DRE, (or best friend, or something I read in a paper or heard about online), those ‘others’ bear some responsibility for the sins of people who trusted them.
The most I can do is give the facts, try to educate people in so far as is possible, try to ‘light a fire of charity and care’ in both clergy and laity, and try to lead by example. . .and pray. The rest is up to God.