nah on reddit, there is active moderation and users self regulate and you don't see real scum and villainy unless you sort by controversial(or seek out a subreddit that sucks)
in any irc it's constant and due to the inertia of users, even if you come back a month later the same user will probably come back and say the same dumb stuff to you instead of you finding someone new to talk to
I used IRC a lot for some time a few years back. I avoided the big channels like the ones for javascript and python, and stuck to smaller (< 100 people) channels. People were very nice, responsive and helpful. At one point IRC channel-presence became one of the main criteria by which I chose new technology to work with: it correlated with something good if a community maintained a good IRC presence.
Same here, if the newfangled hipster stuff doesn't have an irc channel it doesn't have enough of those really old people who again and again watched their stuff crumble in their hands for reasons they were sure were not going to happen. Just picture them sitting there silently raging at the invasive species that are colorful unicode smiles looking back at them from what use to be their purist text interface. How can you not love a place like that?
I think the community has a lot to do with it and each channel is often its own community and culture, even on the same server.