- Australia has laws that about child sex tourism aimed at those that go to Asian countries with lax laws or enforcement. These crimes are committed in other countries [1]
- Foreign financial institutions are subject to FATCA when serving US customers, an issue that has made it difficult for US expats to even open bank accounts in some jurisdictions [2]
- Australia has some pretty strict insider trading laws such that two foreigners who trade in inside information about an ASX listed company while they're on foreign soil (may) have commited a crime in Australia
- Sanctions on the likes of Iran and North Korea prevent US companies or persons from trading with entities from sanctioned states even if such transactions take place entirely on foreign soil.
- US citizens living in other countries are required to file taxes with the IRS even though during the tax year the citizen may never have stepped foot on US soil and any income is earned and paid entirely in foreign jurisdictions.
So I'm not saying GDPR applies or doesn't. I honestly don't know. I'm just saying not being in Europe and being small aren't the automatic defenses you seem to think they are.
[1]: http://www.thejakartapost.com/news/2017/12/13/australia-intr...
[2]: https://en.wikipedia.org/wiki/Foreign_Account_Tax_Compliance...