You’re only saying that because they’re insulating you from the effect of this happening. If Costco had to raise rates because people were sharing memberships and members didn’t want that enforced, you’d complain about that too. Again, it’s odd to me that you’re complaining about them protecting the very benefits that you’re paying for which others are not. Unless you have some magic way to prevent non-members from using benefits that doesn’t affect members, your demands are unreasonable.
The gym analogy isn’t a false equivalence. If Joe Schmo lets his neighbor use your membership, it does affect you and it does so in the same way as it does at the gym - more traffic, less access to product, more upkeep, etc. and none of which they’re paying for but you are. I don’t understand why you’re ignoring the ways this affects you simply because this also affects you.
DRM is a a false equivalence. This is not immaterial goods like Intellectual Property. This is physical goods at physical stores of resources that are physically limited. It’s not the same thing in any way.