Eh, the Internet is infant. Remember the old forums where people posted before registration was an idea? We're still feeling our way through this and eventually, it will sink in that people who contribute meaningfully to a community will be accepted, while others will be banned or ignored. I expect things to only get better as the technology tightens up and bypassing functions (like IP tracking to keep jerks out) gets harder.
On the matter of manners, I've learned to not take people so seriously, those who reply with barbs and taunts. I've made better use of the ignore function and am learning to carry this around in my personal contacts outside and especially at work. The Internet is what you make it.