Definitely wanna make it harder. but as it stands it takes out about 2 thirds of applicants. I get feedback such as "I can't submit any data on that page because there's no form to submit". -> people with certificates and 8+ years of experience according to their CV.
You overestimate many people out there. These are the people I wanna filter out. Even if this is the first time you see an API endpoint like this, it's a google search away to figure it out.
As it stands it tests for:
- reading docs;
- using google;
- detail-orientedness;
- knowing how to use git;
and that's about it. Many people do not pass this test in the real world, HN is a very specific demographic with a lot of skills compared to the average person who calls themselves a developer.