ngruhn parent
It's probably just the syntax
I think it goes beyond that.
TLA+ requires you to think about problems very differently. It is very much not programming.
It took me a long time (and many false starts) to be able to think in TLA. To quote Lamport, the real challenge of TLA+ is learning to think abstractly.
To that, I think plusCal and the teaching materials around it do a disservice to TLA. The familiar syntax hides the wildly different semantics