They don't think they have anything to hide because they think of it as "evil activity"
Reframe it, like sure you are not doing anything bad but these companies don't care about criminal or evil behaviour. For them you are like livestock you only serve one purpose: making them money, there are no morals involved. They would sell your data to absolutely anyone for any reason! YOU can't think of anything bad they could do with your data because YOU are not evil but THEY absolutely are. If an evil person wants your data you shouldn't give it to them because they WILL find a way to use it against us, its a law of nature just like gravity.