Very simply, we are supposed to dress for God with the best we have. He sees and notices each and every one of us from the moment we walk into His presence - and we see Him face to face in the Host. He definitely sees how we dress to come to see Him and He demands not only reverence in His presence, He also demands what goes with reverence, which is modesty, immodesty goes with irreverence - and God hates it.
The whole idea of ushers acting like the SS is altogether absurd. Ushers, among their other duties, are supposed to watch over the sanctity of the place, hopefully in a charitable manner that befits the occasion, but they too will answer to God for letting in those dressed immodestly, for not doing their duty if they do nothing.
There will come a time when each and every one of us will stand before Him naked (and accused), but that time is not now and definitely not at Mass.
Lack of reverence in the conciliar church has no place at the Holy Sacrifice, snip from the below video....
"....God told Moses: "Come not nigh hither, put off the shoes from thy feet: for the place whereon thou standest is holy ground".
Now this passage tells me, and I'm sure it tells you, that there is a need for reverence toward almighty God in His precinct. He gave an explicit instruction here to Moses, to do something to indicate that reverence was called for, to assume a particular demeanor, to remove his shoes, and to be aware by his gesture and by his demeanor, that he could not act in God's presence the way he acted in other places and in other circuмstances..."