Answers to halacha questions quote halachic literature. The vast majority of the halachic literature comes from more than 150ish years ago, and so it comes from an orthodox (small "o") perspective due to the fact that non-orthodox streams of Judaism didn't exist that long ago. Of course there were always less-observant Jews, but they were not trying to justify their practices halachically.
It is only recently that Conservative Judaism (among others) was created and started to attempt to provide halachic justifications for more liberal practices. This site does not often rely on these sources because they are usually seen as utilizing flawed reasoning. We don't have any policy against posting such answers, although they often receive negative votes due to their (often blatant) misinterpretations of halacha.
But in many cases, I suspect that the less "strict" interpretations and applications that you have seen from your Jewish friends doesn't come from misapplied halachic reasoning, but rather doesn't have any halachic justification at all. I don't know your friends, so I don't know this to definitely be the case; however, I know many Jews for whom strict adherence to halacha is not important. They may or may not be aware that their actions violate Jewish practice, but they do them anyway. Such actions are unlikely to be endorsed on Mi Yodeya where we attempt to provide factual, sourced answers to questions.