Has it ever occurred to you that your users can (a) see all requests you make to third party services, including your credentials and client secrets, (b) modify and replay those requests at will and (c) spoof responses from those services?
Which brings us back to the original question you responded to above. Contrary to your odd views of how software is architected, issuing HTTP requests from the backend is both normal and common enough to be banal. Node adopting the fetch API is generally a good thing as it allows JS developers to code against the same interface whether they are working from the frontend or the backend.