Well yes, of course people have priorities over dressing but I doubt anyone here is starving their family just so they can buy a bespoke suit. This place is one of the most thrifty threads i've been to and that's a good thing. I mean just look at people bugging Carlin for them AE deals.
Also, blogging has become a job on the internet, they get paid to do it so if those who are single and work at Urban Outfitters as a day job, blogging provides an extra income so it becomes part of their priority. Hell if I got paid to go shopping, dress up and take pics, hell I am not going to say no to that and I am guessing many here wouldn't either.
To others, it is a touch of fame or notoriety, so let them be. Plenty of people are shallow like that, I mean look at NT, people always trying to be the first to make that joke in new threads to get thumbs and a few making multiple troll accounts so they can give thumbs to their own posts.
This has what the internet has evolved to and you just got to roll with the punches or ignore it.
As for dressing comfortably, you do know that once you are used to dressing a certain way, anything else becomes uncomfortable? I used to wear Phat Farm jeans and once I switched to slim jeans, anything that fits slightly big automatically feels weird and awkward. Your body adapts to it, just like with working out, you do the same work out all the time and your body will hit a plateau. I only use that analogy because you mentioned being fit as a priority to others and thought it'll help you understand.
So those who wears skinny jeans, they aren't exactly killing themselves, it is completely possible that they are very comfortable in it.
Not everyone has to dress for the occasion too, people won't know what I am doing before or after if they see me in a suit at the supermarket so I really shouldn't care what a person I will likely never see in my life again thinks. This is exactly what happened when Russel Wilson was posted in another thread wearing a suit in a Nets agme, people were like WTF? You in a game and you wearing a suit? Get the f outa here! But then it was revealed that he just came straight from doing David Letterman show so again, people shouldn't judge someone from a single pic or a single location.