And even if not, your CI tests take hours to run because of all the network calls.
Automated tests that do real calls to 3rd party services are essential too, but they should almost never be part of your standard CI scripts that get triggered by every push.
But I think the article was mostly talking about mixing network/http level mocking with business logic tests, which I'd admit isn't always ideal, but IME complex test cases often require some level of compromise.