May not be that rare. Math requirements for CS majors at some well known schools for CS:
Stanford: calculus 1-2, discrete math, probability theory
CMU: calculus 1-2, linear algebra, math proof methods, probability theory
Berkeley (L&S CS): calculus 1-2, linear algebra / differential equations, discrete math / probability theory
Berkeley (EECS): calculus 1-2, multivariable calculus, linear algebra / differential equations, discrete math / probability theory
MIT (6-3): calculus, multivariable calculus, either linear algebra or differential equations, discrete math
Note that the first three are non-engineering based CS majors. Of course, the courses listed above do not include junior/senior level math-like CS theory courses (algorithms and complexity, theory of computation, etc.) that may be required or optional.
Bottom line is that a CS major should be good at math and math-like thinking, although calculus-type math may not be used as much as discrete math.