I think the issue of what one wears to Mass is a superficiality; a manifestation of the distractions we lumber ourselves with.
It is undoubtedly a fact that a lot of people judge others by their outward appearance (which is why I wear my best clothes to Mass when I am involved as a Minister of the Word or as an Extraordinary Minister of the Eucharist, not for my own sake but so as not to distract from the importance of the celebration), but that is a weakness of the human condition and not something to be encouraged I would suggest.
Are we to assume that the creator of the universe is at all interested that a dishevelled tramp does not come to worship in polished ‘sensible’ shoes and a clean starched shirt and tie?
Well I guess there is a pretty fundamental disagreement here Hugh. In the end externals are not all but they are important and they bespeak what is going on in the inside. Agere sequitur esse. We are body persons. We are not not abstrations or disembodied intellects. Since we have bodies, what we do with them is important and manifests our soul to a large degree. I don’t think that our concern about this is a weakness but is rather a reverence for how we are made. It is true our concern about such things can go out of balance but in essence it is a valid concern
I agree with Hugh’s point here
Ideo dico vobis, ne solliciti sitis anim? vestr? quid manducetis, neque corpori vestro quid induamini. Nonne anima plus est quam esca, et corpus plus quam vestimentum? Mathew 6: 25
Ultimately all a set of clothes tells one about another is that they own that particular set of clothes. There are many crooks who don a pinstripe and sit in the pews and many a saint with nary a stitch; and a set of vestments is no guarantee of what lies at the heart of a person unfortunately.
A suit and tie is a cultural fad as was the Ruff, doublet, slashed leather jerkin, and paned trunk hose with codpiece in the 1500’s, and will no doubt seem as ridiculous to people in 500 years time as that ensemble seems to us now.
13 Tunc dicit rex ministris: Ligatis manibus et pedibus ejus, mittite eum in tenebras exteriores: ibi erit fletus et 
stridor dentium.
If you read Monsignor Pope’s original comments, you’ll see that his list is not about particular articles of clothing in themselves, but rather as falling under the category of “appropriate semi-formal attire”, which category is the focus of his comments.
Ultimately all a set of clothes tells one about another is that they own that particular set of clothes *and chose to wear it today*!
The passage you cited is about commissioning the disciples for missionary work! It’s about needs being met, not choices (as the later passage from chapter 22 is).
Yes, I agree with J. The text you quote is about not being anxious that we will lack clothing and other essentials. Further, Hugh your conclusions are far too extreme. It is just not common sense to say that clothes don’t matter at all or taht nothing can be concluded from them. I would concur that too much could be made of them but you are but it’s just plain wrong that clothes say nothing at all.
It makes sense to me that since clothing is frequently more symbolic than practical, it is appropriate to show through some gesture (men putting a ribbon around our neck for special occasions) that some things are particularly valued. It is a particular cultural expression, but these are necessary. It does not make sense to enshrine one particular historical manifestation (e.g “the way people dressed in the good old 1950’s”) of respectful attire. To suggest as a theological statement that God, as “King of Kings” demands our use of a tie or that women wear a dress rather than pants seems absurd. Indeed, if this were the case we would be obliged to wear our tuxedos and ball gowns. God has made it clear through the Prophets and Jesus that clothing too quickly becomes a hang-up for people, and especially displays of clothing in a religious context…The symbolism of clothing can too easily shift from a show of respect to simply a “show”.