It looks like it's a US-based company without enough of a European presence to fall under their jurisdiction.
They can say this all they want, but if you have no presence in the EU, and your jurisdiction does not have any agreement to apply GDPR regulations to you, then this is at most a strongly worded request.
Barring explicit agreements to the contrary (treaties, extradition agreements, etc), by definition a country's laws are only enforceable there.
If PDL has no business in Europe, no plans to expand there, and there's no treaty or other agreement making the provisions enforceable against them, the EU can say whatever it wants but PDL has no legal obligation to do anything about it.
(Assuming anyone were bothered enough to actually do this, of course.)
On the other hand, if you never fall under European jurisdiction in the first place, you're free to ignore them, just as you can ignore Thai laws against insulting their king. One very important thing to note is that setting foot in European soil will expose you to their jurisdiction, so you've significantly limited your freedom of movement, but if GDPR compliance is a bigger deal than that then "just never go to Europe" can be a viable strategy.