Honestly, that doesn't seem that non-intuitive to me. Certainly missing opening and closing brackets, but if closing with fi is a common idiom of old languages. The rest doesn't seem that bad. Just verbose.
I guess to me it doesn't read that much worse than "if (!(x < 100))", which is somewhat bad form, but not unreadable. (More likely would it have been "if (!aboveThreshold(x))". I know I have seen similar in some lisp code. At least, I have seen "unless" before.
Don't take my comment as my rushing out to embrace TeX. I just don't think it is nearly as bad as its reputation.