To play the devil's advocate, castling was a pretty late addition to the rule of chess compared to most other rules, so there used to be a game called "chess" which did not feature castling (nor the option to move pawns initially by two squares). Some regional variants of chess https://en.wikipedia.org/wiki/Indian_chess did not feature castling fairly recently (and differed from mainstream chess only by a few points), and there are stories of Indian chess players who became masters in Europe (as late as the early 20th century) even though they had learned to play without castling (can't recall the name of the one I had in mind, but there are such anecdotes at least for Mir Sultan Khan).

I agree that it would be nicer if the implementation followed FIDE rules, though, and that not being able to castle significantly changes the strategy.