"I just flatly responded that it was far less readable, even if I could condense a half-dozen lines of code down to one."

Express the exact same thing, in 1/6 the code, and somehow the shorter code takes longer to read and understand?

You don't even attempt to express why you find the shorter code harder to understand. Or show code written both ways, to argue why one is better than the other. Or anything at all to support your claim.

Based solely on what you're telling us here, I'm siding with your code reviewer on this one.