Firstly, they are called "harnesses" and not "leashes." Last time I looked, I had two children and no dogs present in this house.
Secondly, it's all about safety. There are rude, obnoxious and insular adults at WDW, which makes my use of a safety harness essential in some situations. We have one that is a special chest harness - not a very long strap at all. The older models that went on wrists can be very dangerous for all parties involved.
Thirdly, not sure why anyone would feel the need to comment on them in the first place. It's just like people who comment on: strollers, wheelchairs, scooters, etc. If they are being used properly, then they are being used for safety or medical reasons and there is no reason anyone should have a problem with that.
Lastly, not sure why anyone should be commenting on something they have never tried? Why do I need approval from a stranger on how to keep my child safe? As long as I'm not harming you or your children, it shouldn't be your concern. Harnesses have their places - they ensure child safety. Not sure why any adult would have a problem with that? We have received many stares from uninformed and ignorant adults, as far as I'm concerned, while using our harness. Does it bother us? Nope! I am in charge of my child's safety and so I can handle some looks from strangers who have no business commenting on my child's safety in the first place. It's funny, last time an adult stared at us while walking through Epcot, they were smoking, in an undesignated smoking area, I might add...Now, that is something that we can have a discussion on as that behaviour affects our asthma. Totally different from parents who properly use safefy harnesses in order to ensure their child's safety.
Tiger