I think that was a necessity. The machines were built to do math, and at the time they didn't have fancy modern compilers that could do pure magic transforming human-convenient expressions into amazingly efficient machine code. So they had to either design the machine to do the required operations in hardware or make programmers do similar magic in their heads.
You might be interested in reading The preparation of programs for an electronic digital computer (1951) By Maurice V. WIlkes, David J. Wheeler and Stanley Gill. That's the textbook they used for the first programming course (in Europe) using the EDSAC. The interesting thing to me about this book is that the topics discussed can still be found in some way in "modern" introduction texts to programming.
Part I
1. The design or programs for electronic computing machines
2. Input of orders
3. Subroutines and parameters
4. Library subroutines and their use in constructing programs
