You might not have meant it to be about toddler rights, but there are a subset of parents who get all up in arms and make it about toddler rights.
Here's the thing though. People with broken legs, in wheelchairs, etc - they know they're slower, and they tend to walk to the side so that people can pass if necessary. If they're not, you can ask - and they tend to move, and even apologize for getting in your way. People walking slowly while on their phones, they're in the wrong, but again, you can ask them to move and - if they have any manners or decorum at all - they usually will.
Toddlers, on the other hand. You can't reason with a toddler, as so many of the parents on this thread have come out to tell us. But it's more than that - not only is it reasoning with a toddler like trying to teach a fish to ride a bicycle (i.e., completely pointless lol), but it has the added disadvantage of the parent of the toddler telling you off. How DARE you speak to little Rufus! You're not his parent! His PARENTS make the decision for Rufus's care, not you! And you're selfish, they berate you, for having the audacity to have wants and needs that don't line up precisely with Rufus's desire to toddle right exactly where you need to walk!
So there's two different things going on here. Most people above the age of five or so can be reasoned with and helped to understand that they're doing something that's inconveniencing or upsetting someone. But at toddler age, not only can the toddler not be reasoned with, but you too often get abused for even trying by the parent, who also apparently cannot be reasoned with.