Here is a one-dimensional diagram of players "true" skill (note that this is LOGARITHMIC not LINEAR)
level 1 Bronze Silver Gold Plat Diamond V Diamond I Masters Challenger LCS World Champs
|-------------|---------|-------|------|--------|-------------|-------------|------------|-------------|----------|
All players are on that line. Now, how to measure "true" skill is difficult (mode, median or max?), but it's uncomputable from our perspectives anyway.
There are the two dichotomies of player skill: micro and macro. Keeping your "true" skill constant, it is impossible to improve one without giving up some of the either. If you improve one but leave the other constant, you improved your true skill.
In addition, there's a strong argument that could be made that having a much higher standard deviation of "micro" skill is better at lower skill levels, but "macro" is more important at the top. You can see that with Hai being used in C9 for 1.5 splits despite his wrist/lung injuries: because his macro was so good.
Scripting gives a HUGE benefit to your micro (auto-CSing, flashing impossible skillshots, etc), and a modest benefit to your macro (FoW trackers, ward timers). Players like the Katarina scripter, have really poor macro, but were able to catapult themselves to much higher ranks, despite completely awful macro.
Let's say that the Katarina player have a "true" skill of Plat when using scripts (this is overall true, he did hit plat in 2 weeks).
His skill rating would look like this
Macro |---|-------------------------------------------------| Micro
When playing against opponents who are scripting who have very poor macro, it becomes obvious that they have "trash" decision making. BUT they don't become a "trash" player: their "true" skill level might be just the same as yours. Non-scripters CAN have such mismatching micro/macro scores, and will deserve their rankings just as much.
However, what happens when someone like me? i have pretty decent macro, but my non-teamfight micro is not very good 
Macro |-------------|-------| Micro
Suddenly it becomes this (in comparison to my old "true skill"):
Macro |-------------|-----------------------------------------------------------| Micro
Suddenly, i am capable of shooting up. All 50 games on the way up become trivial: i smash my lane opponent, and coordinate with my team. Since i'm auto-CSing i can even type and play at the same time! i don't look like a scripter: i look like a SMURF! Because, i am, effectively smurfing at a level of play much lower than my own.
Once i get to Diamond, because my macro was "alright" before, i might not be as obvious as more micro-inclined players.
Due to our typical "Normal Draft" skill levels of gold/low plat (mostly due to duoing with lower MMR folks), when we do see scripters, we see the ones "on the way up". They are poor-macro players who are towards the end of their climbing, and their poor macro is really catching up to them. i'm sure if you played more SoloQ or only played Normals with Cow, you'd see more "moderate macro" players in mid-plat since they are the ones who benefit the most from scripts. Promos to Diamond V you would see even more!
That said, i wouldn't be surprised if macro-inclined players are somewhat less likely to script (despite being the ones who would benefit the most). Macro-inclined players are more likely to be "Johnnys" than "Timmys", and most Johnnys are going to see scripts as abhorrent.
