Hey @Sleepy,
No, he doesn't. He says:
He says you can't do it with normal Keyboard Maestro actions, BUT it might be possible via an alternate method.
He then goes on to show how how to use that alternate method in a subsequent post.
People don't intentionally post complex macros demonstrating how to do something that doesn't work.
If you haven't designed and built software with Xcode and Objective-C/Swift then you have no basis for understanding.
Even a relatively trivial change is minutes (or hours) of work and has the potential to break things that will cause many more hours of work.
Peter is very happy to entertain suggestions, but he has his own notions of how to do things.
If you really want a feature you need to make a strong case for it and do more than just say “I want feature x...” The latter rarely works.
That said I personally don't like slider controls very much – especially when they don't have an alternate numerical input field.
And that said – you may or may not have noted that you can use a variable input for the fuzzy attribute when building the action from XML.
-Chris