I agree with Rich, and I find the excuses truly lame. I also think that some of this is cultural. There are poor immigrants from poor (3rd World) countries who dress up here to go to church. (Some are Protestant, some are Catholic) Many stay in their finery all day on Sunday. When I say “finery” I do not mean designer (expensive) clothing, and I do not mean cocktail apparel (over-fancy for church services); nor do I mean Dressing to Impress. Clever people from all walks of life know how to dress merely respectably on very little money. Whereas it would never occur to them to purchase 4 pairs of flip-flops to interchange on any particular day, or designer jeans near $100/pr, they have enough imagination to know how to stretch a dollar, so that non-designer jeans can function on 6 days of the week, 1 pair of flip-flops will suffice, one “Sunday” outfit (non-ultra-casual) can be afforded, as well as a few outfits for work (whether office, manual, whatever).
Contrast that with many middle class people who choose to purchase designer jeans & multiple pairs of flip-flops, and buy frankly overpriced casual clothes (speaking of needing to Be Seen), yet complain about the “expense” of a single outfit that could be worn not only to church, but to any number of “formal” (respectful) occasions: visiting court, going to a job interview (hmmm), attending a sacramental occasion, attending a graduation or wedding, etc. I know for a fact such people are often forced to go and purchase an outfit for these occasions when they occur in their lives; interesting that ‘suddenly’ they are able to “find” the money.
No one is being “judged” by what they wear. It has nothing to do with social approval. It has to do with personal thoughtfulness, awareness of the moment, and deliberateness. Just say you can’t be bothered to be deliberate, then, about externally distinguishing this Sunday occasion from going to the grocery store or walking the dog. The little effort expended is quite a statement, but OK then.
To be clear, again: When I see others at Mass, in cutoffs & flip-flops (or pajama bottoms

) I treat them as nicely as I treat everybody who is dressed nicer than that. I don’t internally judge them, either. I’m just making
a general observation, as I’m sure Rich is, expressing my overall disappointment with a modern culture that is stubbornly focused on personal convenience and comfort (The Self), as opposed to an awareness of joining together as a purposeful community to make a statement about Sunday Mass being a radically different opportunity than the rest of our week.