Validation Issues

I feel like I am not understanding something with the JSON:API Schema. I attempted to validate my JSON document against the JSON Schema provided for JSON:API at https://jsonapi.org/schema, and ran into dozens of errors that seemed to go against what I had read in the specification. For a sanity check, I tried validating the document on the JSON:API home page, and got dozens of errors as well. Should I be able to validate to the schema document the example on the home page?

I used https://www.jsonschemavalidator.net/ for validation as well as Postman’s built in jsonSchema method (which uses AJV, IIRC)