We plan on using a sling - either a Kari Me or a Mei Tai. I don't massively like the concept of buggies/prams in principle but dear god - mentioning that amongst my friends has me labeled as "massively alternative". HA, whatevs :)
I do get tired of explaining that the more you carry your child, the easier it becomes simply because you get used to it (not exactly rocket science!), and I really dislike our culture of extending our babies far away from us, and prefer the involvement in my activity that a sling affords.
But - with the usual caveat (because god forbid someone doesn't realise it) of horses for courses, OP mainly you're just guilty of being a bit ignorant about slings. You've said yourself, on reflection, it was the 5 year old on the scooter not so much the baby in the sling.
They're not dangerous - Jesus Christ, I grew up in a seaside town and my dad is a cab driver. Mid season, the amount of times I've been in his cab and he has literally swerved out of the way of a holidaymaker pushing their baby out into the road first, with no regard for traffic on a busy road, made me swear never to use one 
And what, there's never endless debates over which kind of plastic/metal contraption - sorry, prams! - is best either?