I respond to them by beating them with my ICs. But sometimes my friends go and say "Chaingrabbing is not pro and people that do it and claim they're pro aren't." or even say "There's two people, it's like a 2 vs 1, play someone else like Ganondor cause he's not cheap". It's the norm for me to hear that. Sometimes when people get angry at me, they use Pit and constantly use his spinning-like-a-wheel move.
If that doesn't shut them up, I just tell them to play ICs and see if they think just by playing ICs, they're good. Or I just beat them down with my DK.
It doesn't bug me, and besides, when were people thinking that the ICs were "kewl" in the first place, since many people haven't heard of them? Heck I haven't even heard of them till a year ago. Also there are people like that, just ignore them.
You gotta admit, the ICs moves aren't what you call "awesome". Look at WeeGee moves and look at IC's. Mabye that's why people don't call ICs' moves "cool".