I think I disagree! Calculus is great and all (truly), but logic, boolean algebra, probability, statistics, even linear algebra all have really interesting and useful insights and are very approachable. I'm sure there are other maths I've never encountered that can also be enjoyed with minimal pre-requisite knowledge, though that might be more in the 'abstract and difficult' territory.

The bits you need from calculus to approach those other subjects is also very minimal and approachable relative to the content of a calculus pre-req (where applicable).