That is using "birthright citizenship" as a synonym for jus soli birthright citizenship. This article is looking at birthright citizenship more broadly and is including jus sanguinis in its definition of birthright citizenship. Virtually every country[1] has birthright citizenship under this broader definition.

[1] The only exception I'm aware of is Vatican City, where citizenship is based on appointment to a position in the church.

That list seems off. Multiple European countries that I know of should be on that list.

Are other countries more, or less strict?