Come on, of course that's ridiculous.

Of course a reasonable person would expect to be able to cancel a subscription without needing the device it was created on when they used an account that you can log into from basically anywhere.

If I bought an iPad and subscribed to something, and then accidentality dropped it off a cliff, or out of a plane, or lost it in the sea, and I decided you know what, I don't want any more Apple stuff, you can be damn sure I'd expect to be able to cancel any subscriptions I had on that account (you know, the account you can log into from any computer or device), from somewhere other than on the device itself.

Suggesting anyone should expect otherwise is insanity.