I don't believe that. These companies want to make money and would love to make more. They also don't want to lose money, so they find ways to decrease risk. Their lawyers probably tell them what's risky and draw the line there. If you don't want them making these judgements then voters should tell their regulator exactly what is and isn't ok.
And neither does regulation preventing purchasing porn either. But be explicit about what’s ok and what’s not if you’re going to regulate it. Otherwise companies decide for themselves and we end up here.