It's nothing to do with balance or lore.
Let's say escort targets player A, and witch decides to control escort into themself (alternatively, trans transports themself with player A)
Now their action can be thought of as a statement. If the action is successful (no roleblock), it's true. Otherwise, it's false.
Since the action is attempting to make the escort visit the person doing the action, the action is basically saying "This statement is false."
THAT is the real reason trans and witch are rb-immune. It's to prevent paradoxes.