My point which you seem to have missed is that a heat sink on a pipe is ridiculous. And I was answering your question, "Has anybody here actually touched a working heat sink?" So once again, yep, I've used many on brushless motors on my RC helicopters, and yes they do get hot.
Okay, we're obviously talking at cross-purposes and I don't know who pissed in your Corn Flakes, but "has anybody here actually touched a working heat sink" was a rhetorical question. I agree that a heat sink on a pipe is ridiculous.