...I don’t know why so many FA insist on wearing bras that have no support. I get trying to fight beauty standards and all, but a well fitting bra shouldn’t be considered one of those impossible beauty standards....
There's a couple of reasons I can think of for that:
First, if you're an outlier size (and all of these fatties, including the ones with small boobs, are), finding bras that actually fit is difficult, time-consuming, and frustrating. You have to be really fucking determined--and you have to know what a properly-fitted bra even looks like in the first place, or have the help of someone who does.
Ideally, there will be a specialty store that stocks your approximate size, and has fitting staff who knows their shit, within driving distance. But an awful lot of women will have to go through a few cycles of ordering bras online and returning the ones that don't fit, which not only takes time, but can get prohibitively expensive (because you're looking at $60-100 per bra, in that case).
Different manufacturers fit different body types, and certain styles will fit an individual woman better than others. So if you're like virtually all of the fatties here, who have never owned a properly fitting bra in their lives, and have no baseline for what might fit best, you will have to try on a lot of different bras before you start hitting the target, and even more until you find the combo of brand, size, and style that is your own personal bulls-eye.
Even a woman who generally feels good about her body is going to feel really demoralized at some point during this process. For fatties who claim they love their bodies so much, yet can be so easily triggered by diet talk, or another woman getting WLS, or being weighed at a doctor's appontment? MAXIMUM TRIGGERING ACTIVATED.
And to top it off, the bras that make your girls look great under clothes, and that are actually comfortable, are not likely to be cute in those sizes. You may be lucky to get them in black, instead of just white and beige--forget fun colors and prints. It's easier to deal with that if you assume bras are underwear that nobody else is going to see, but if posting pics of yourself in your underwear on Insta is a core expression of your identity, I guess you're going to feel pretty fucking oppressed, and need to go cry and eat a cake before making a self-pitying post about non-inclusive sizing and how fatgirls deserve pretty bras too to Insta.
And second? None of these fatties are staying the same size. They're all getting bigger, mouthful by mouthful, month by month, year by year. That means the carefully-fitted bras one of them might buy today aren't going to fit in six months, or a year. Going through all that frustration just to get a bra that fits isn't going to happen because none of these fatties can tolerate frustration in the first place. If one actually did, she sure as shit wouldn't go through it a second time.