Yes, exactly. I didn't mean to say that all "free" things are a net neutrality problem, only that policies which affect different traffic differently are still problematic when they're free.

For example, if T-Mobile started charging $10/month to access Spotify on their network, that's an obvious net neutrality problem. What I'm saying is that if T-Mobile lets you access Spotify for free on their network, that is also a net neutrality problem, although many people see it as just a bonus.

Stuff where an entire plan is free is fine. It's when different traffic is treated differently that net neutrality comes in.