Because I don't think your average user will bother to call. They will be made aware of the problem - perhaps it will come up in conversation at the water cooler - but I doubt they will care enough to place that actual call. I wish there was more call to action - and more importantly, an easier to read info graphic.
You're right. Most users won't. But if 1% of users actually do that's an enormous impact. Right now, there's nothing to even push them in that direction. Even users who get riled up will probably feel their work has been done by signing that aimless petition and not bother looking up how to contact their representatives.
