I think their argument would be stronger if DRM opponents were more specific when talking about harms.

For example, DRM is used to spy on users. The article notes that DRM'd software can maintain a connection with a server and user actions are reported and recorded on the server. They need to go one step further and explain why this is bad and list some of the real damage that has caused.

If they don't, it sounds more hypothetical and people just aren't going to get all that bothered by it.