An all-you-can-eat restaurant where customers don't eat anything and you still keep charging them until they notice months or years later is indeed exploitative.
For something like an apartment, there's reasonable justification for long-term contracts and continuing to charge people without regard to use, in that it's an expensive good that has exactly one user at a time and where it can take a while to find a new tenant.
But that entirely vanishes with most internet-based subscriptions. If I stop watching Netflix, they stop experiencing marginal costs for me. If I get excited about a NYT subscription but then stop reading, it's the same deal. Nobody went out and bought another server just because I signed up. I could cancel at any time and they'd have to let me go. If they keep charging me when I'm not getting any value, then it's not a mutually beneficial relationship; they're just exploiting me. And indeed, maybe they were exploiting me from the get-go if their intent was to just get my money in without regard for whether I was going to get anything out of it.
People who take money without providing value are at best economic parasites, but quite a lot of them are just scammers, grifters, and frauds. Which is exactly why a law would be especially valuable here, so that their time and attention were devoted to some socially positive activity.