They didn't say the petition was to give drivers the right to "influence" in a vacuum as it it could be interpreted as anything, such as "influence the company" or "influence their pay scale" or "influence company policy", it was specific "influence decisions about their work."
you could have just as easily quoted any other word, "decisions" "about" "their" "work" as those words are not "control" either, but when you put it all together, "influence decisions about their work" that sounds a lot like control.
Contractors are supposed to have control over their work already, if it makes it easier remove "influence" and if you think there is a more fair interpretation of "decisions about their work" lets have it.