So when the poor fail to cross an additional hurdle of saving for something which shouldn't be necessary whilst not having enough money to feed themselves properly, which the wealthy don't need to worry about, or simply refuse to go through such unpleasantness in order to obeise themselves in front of the systems which oppress them, you accuse them of lacking self-discipline, and use that as an excuse to deny opportunity from them and keep participating in their oppression.
A perfect example of why suit culture is not just unpleasant, but is actively evil, and anyone ethical should help resist it.
One problem with it is that the bizarre notion that a suit is "professional" is a tool of social exclusion, and anyone wearing one where it's expected will support the notion, and hence help to exclude people who aren't interested in them or can't afford them.
Also simply just having to abandon my own personal culture and yield to a hateful culture where we judge people by arbitrary qualities of the clothing they wear is an awful feeling, and if I could do this willingly, I wouldn't be so good at demanding correctness elsewhere, and hence writing disciplined and secure code. You want to be able to be yourself at a place you'll be spending a significant proportion of your life. The suits game is wrong on multiple levels, and utterly rejecting it is part of my being.
How about the entirely unnecessary, bigoted coercion and force used against them by society to incarcerate them, which they wouldn't have to suffer if they were addicted to something mainstream, i.e. alcohol or tobacco?
Having your life ruined merely for being different is something which should attract sympathy from anyone.
The first question is not actually how you can create such a culture, but whether it's actually a good thing in the first place. You seriously need to evaluate this. One of the primary means of being secure is not trusting others. But trusting others is an incredibly useful tool to get things done, and it may be worth taking the security hit. Stand on a crowded railway platform, and you're trusting so many people, each of whom could push you off and kill you so easily, without even thinking about it. Without trust, society itself would be impossible.
So for example, if everyone believed they were immune to the security risk of terrorism, this would very obviously be such a good thing for society. There have been security economic analyses done of various security measures recommended by security guys, thinking their users to be fools who just wouldn't listen, which established that the users who ignored them were actually completely right, that the cost of implementing these measures was hundreds of times greater than the benefit of preventing the attacks they were effective against.
A security professional who thinks doing things securely must always be a priority just because that's his field, instead of taking the time to gain a more holistic understanding of the situation, deserves to be ignored.
We can predict everything, except the future.