Agreed that the mile and the 1500 are two different things, and, as you said, most people come through the 1500 in a mile race 1-2 seconds slower than they would've had it been only a 1500 race.
I also agree that the comment that none of us understand how good a 3:30 1,500M is in comparison to a 3:47 mile was very patronizing.
I'm not 100% sure that conversion rate is completely accurate. To be completely honest, I think I'd be more impressed by a 3:44 mile than a 3:27 1500, although it's obviously close. I think El G's 3:43 mile should get more respect than it currently does.