I'd guess it's counterintuitive because making your goals public implies some sort of accountability ("I have to do this, or my dad / partner / 1k followers will be disappointed"), but that won't work unless somebody actually holds you accountable for (not) pursuing your goals. Your dad / partner / 1k followers won't express their disappointment in you or try to push you harder when you never even started writing your novel, for example, because they'll probably just think you gave it a try and didn't like it much (at least that's what I think when I'm the person being told about someone's goals).

There are studies about reduced commitment when intentions become public (like this one [PDF warning] that's been published in a highly-rated journal, though I don't know if their methods 100% check out [e.g. they only looked at commitment over a period of one week and used self-reports in the first experiment]). They basically say that your commitment goes down when your intentions become public and you really want to reach that specific goal because it gives you a premature sense of accomplishment (e.g. being an author who writes novels) that reduces your motivation to keep working on your goals.

Maybe making your goals public with an appropriate accountability mechanism (something as simple as gym buddies can help people who want to work out regularly) can help overcome this hurdle.

(idk tho)