The textbook author basically said "Physics: it's kinda right, I guess, if you squint hard enough." Meanwhile, math is over there being all "I am the eternal truth!" 🙄
That highlighted part is the academic equivalent of saying "Physics laws work... until they don't." Thanks for the vote of confidence! Next they'll tell us gravity is just a suggestion that objects follow when they're in the mood.
The mathematician who wrote this textbook definitely got a C- in physics and never forgave their professor.