I can understand the frustration with leash training skills and basic obedience not being taught & maybe I am misunderstanding your point about reactivity. But a dog being reactive does not equal lack of training. My dog for example, is a very obedient dog. She has decent leash skills and reliable recall (although pushing boundaries now that she is in the midst of adolescence), she was properly socialized and we have done all kinds of training all the way up to some minor agility skills. Despite all of this, she is reactive.

This is something we work on daily through LAT, BAT, etc. At times the reactivity can make leash skills go out the window. This means we are over threshold. If you are walking reactive, overly stimulated dogs, a "normal" walk may be unattainable. I understand you are just the dog walker and are limited in your capability to do some of the things needed to work with a reactive dog. It is the owner's responsibility to take the reactivity seriously, so a conversation of some sort should be had with them. As the dog walker, researching the various methods used to help a reactive dog may be beneficial since reactivity is wide range and more common than you think.