We’re social animals. Concern for status within our groups is kind of hard-wired into us. The kind of independent-minded individualism you’re talking about is, for some people, actually just another ploy to increase their status within the group. We just happen to live in a culture that places some value on that kind of spirited non-conformity and prizes the individual, so putting our non-conformity on display can actually be a way of seeking admiration. They want to be seen as “special”, in other words.
People who really don’t care what others think about them are either highly spiritually developed, have some kind of impairment of their social intelligence or are outright sociopaths. People who fall into these categories, though, are unlikely to try to draw attention to their non-conformity.
That said, we do have differing and ever-changing views on how rigid our unspoken social rules should be. Some of us want them to be very restrictive (and drawn to accommodate our own preferences, of course), and so they’ll be highly judgmental and try to police those rules. Others prefer a looser set of rules, and they may press for that by pushing back in a public way against the rules that others try to impose. But we all recognize the need for some rules.
People who ask the “Is it OK to______?” kind of questions are trying to figure out what the rules are. They may not have yet acquired the confidence to assert their own views about how the rules should be (not all individuals among social animals can be leaders, and that’s a very “leaderly” stance to take).