Hebrews 10: 26 talks of if we willfully practice sin after knowing what is right and wrong, then it is a sin for us. It also speaks of being no sacrifice for sins left if we did this. The key word is WILLFULLY practice sin. Its true we do fail at times but yes nobody is perfect. We have to do our utmost to be clean as possible from sin.
Bear in mind there is what is deemed to be serious sin, such as fornication, murder etc.... If these sins are committed then it should be hard to be accepted back in to the congregation but not impossible. But as for less serious sins, (eg) swearing etc...., these although are unacceptable are conceded that we will at times fail because of imperfection. Still it should not be looked at by a faith to be okay.
I do agree with you though, it does seem as though most religions are giving the nod to bad conduct.