They absolutely are completely separable. DRM is one technological approach to enforcing a model on payment for content. There are other models, and other mechanisms to encourage payment or reduce non-payment.
To pretend that DRM is unique, or in some way the natural approach is folly.
DRM is not the implementation or the technology, necessarily.
Those who own copyright want to deny the ability to copy to others, because they fear it devalues what they have. That doesn't make it right, or natural, as if any of that even matters. It just means that a group of people exist who want to be able to enforce copyright. And the opposition to that is, by definition, those who want to be able to make copies of things without the blessing of copyright owners.
If DRM were perfect, there wouldn't even be a technology- or freedom- based argument against it.
To pretend that DRM is unique, or in some way the natural approach is folly.