I 100% agree, if you can sign up without a phone call, you should be able to cancel without one. However, at the end of the day, it's just a phone call. It gets a bit dramatic.
For many people a phone call is not "just a phone call". Companies doing this know why they force customers to call. So did this one when they changed the terms of service recently.
No, it's not the end of the world for most. But it sure shows how they treat their customers.
I would make it a mission to never do business again with such a customer hostile company.
The Stripe angle is interesting, someone should see how Stripe feels about endorsing such behaviour.
You know I want to leave, let me leave and stop being abusive.