im not though. I don't think you need to know measure theory and understand how to formalize probability in terms of sigma algebras to do professional stats.
But I would be very skeptical of a professional data scientist that doesn't understand things like derivative, integral, limit on an intuitive level. I don't know how you would understand distributions without that knowledge
for actual understanding, yes it is. The most basic important results, the law of large numbers, and the central limit theorem both require calculus to understand.
if you make a class without calculus, it is essentially just a bag of tricks and surface level understanding
calculus is the most basic of mathematical machinery, that it is essentially a requirement to do anything else.