For example the ultimate form of DRM is the iOS style where code must be explicitly white listed by some authority in order to execute. This is potentially bad for all kinds of reasons that are nothing to do with piracy.
However any system that relies on absolute centralised trust is vulnerable in a variety of ways.
For example if you were to develop a system that allows for secure , encrypted communications between 2 parties such as GPG.
The platform vendor can enforce a policy that any such software must include a backdoor for their own use, that of law enforcement or for their advertising partners.
Whether such a policy is implemented now or not is not so much the issue, it is that such a policy could very easily be enforced in the future.
As long as open platforms are viable and available the issue is less urgent since people can opt to use these instead.
However when you have powerful companies with lobbying might such as the various content industries who have their own reasons for preferring such a model it becomes a little scary.