Charts that only show telemetric data on a small sample of players is hardly conclusive of what needs balancing on an individual level. They show nothing regarding balance in essence.
Support guns are over-performing right now. How can this be argued?
Well, until relic provides the data themselves, its the best we've got, yes the charts show only half of the story, they aren't really accurate because they include games vs players outside the top 150, but again, nothing else we have, poll sample is quite small, but at least it can show a trend.
That being said, it have nothing to do with ISG being OP.