covid 19 – Is a person with an EU work permit considered a citizen of European Union Member States?

A person with a work permit is not a citizen (to make it simple, a citizen is someone who can get a passport from that country). A person with a work permit way be a resident of that country, though.

But the site you linked has a long list which goes well beyond just citizens, and includes:

people who have the right of permanent or temporary residence in the Republic of Poland or a work permit,

(…)

foreigners with a permanent residence permit or a long-term resident’s European Union residence permit, in the territory of other European Union Member States, a Member State of the European Free Trade Agreement (EFTA) – parties to the agreement on the European Economic Area or the Swiss Confederation and their spouses and children, when traveling through the territory of the Republic of Poland, to their place of residence or stay.

If you are travelling to Poland, the first item is the one for you. If you are travelling through Poland, it’s the second one.