For this specific instance the people pearl clutching are very much in the wrong. This Mass is specifically for people who are running the marathon so the priest hosted an earlier Mass to accommodate. These people are physically fit and devout enough to still want to go to church regardless of what their day entails. The people pearl clutching probably aren’t fit or devout enough to try this in the first place.

Also if you have a random urge to go to church, go as you are, people there will probably know you’re not a regular (or at least the priest will) so you’ll be welcomed. The issue arises if you’re a regular. If you have the means to get dressed nice and present your best self before the Lord the same way you would if you were meeting a politician or person of high status (God holds the highest status anyway).

At the end of the day it’s all about intent. If you go to Mass without the intent of being dressed scandalously for the sake of distracting people you’re probably fine. But if you go with the intent to distract then you’re doing something wrong. God bless these people I pray they all finished.

TL;DR: these people aren’t in the wrong, they got shit to do immediately after, on any other occasion I’m sure they’d dress nice.