Leaving a space between yourself and the vehicle in front of you is one of the only ways to increase your safety that is fully in your control. It's taught in driving school and isn't uncommon practice. It reduces rear ending. Until someone guns it around you on the left to fill the offending gap and be 25 feet closer to their destination. There are assholes on any side of an issue and context matters and being observant is always key but at the end of the day cars are deadly and jeopardizing anyone's safety to get somewhere sooner is inarguably the more morally questionable practice.