yea even back when demo was powerful the scout has always been the main counter to demo since it's so easy to get up close and kill them, and now with the sticky nerf and the medic-buff, which actually compliments a scout holding W (cause now medic can hold W with him) demo is significantly harder to play against a scout (that can aim)
the double jump mechanic literally makes scout what it is and if you combine that with really good aim and 185hp you can literally wreak havoc no matter what league, what division. scout will always be the all time carry class (unless demo/solly gets ultra buffed which is not gonna happen)
it just comes down to aim and your team doing basic damage and space creation for you to secure frags, or even to make plays yourself and take potential 50/50 chance 1v1s (which you shouldnt really take if ur smart anyways)