That's just all the hyperbole Apple gets. Security is one of the biggest strongpoints of Apple. Look at recent Meltdown/Spectre issue, macOS, iOS, tvOS all got fixes deployed immediately, just press a button to install. Meanwhile how many vulnerable Android phones and unpatched Linux boxes are out there.

Vulnerabilities come and go on every system, but Apples is actually very good at mass deploying fixes to their whole product line very fast.