Yes, of course, any defense of Apple must be due to remuneration. LOL.
It's an oversight, I suppose, but a defensible one. Putting management for subscriptions in the AppleID management area of Settings on Apple devices is an entirely reasonable thing to do. For one thing, it means you don't have to futz with a login to get to it.
I'd never use a web login for this. I'm sure most Apple users feel the same. And you have to have an Apple device to consume the subscription the OP is talking about, so ... yeah, seems like a chintzy thing to whine about.
Which was my original point: it's HN, so there must be Apple-bashing. QED.