No, the initial argument was actually about whether the batter at the plate had an advantage when a speedy runner was on first base, due to the "disruption" that the speedy runner caused. The studies that I linked to you addressed that issue - the effect on the batter. It was even argued how the batter would see more fast balls and would thereby hit better.
In terms of disrupting the defense to the extent that it gives the hitter any advantage, the hitter's advantage does not exist. In fact, the hitter is at a disadvantage. In that sense, "disrupting the defense" is actually hurting the offense.
No one is denying that speed is a valuable weapon. Most of the team's advantage comes from the actual stolen bases, staying out of double plays, advancing an extra base, etc.
There does tend to be more balks with a speedy runner on first, so there's that. But the whole notion of a speedy runner disrupting the defense is largely overstated.