Coercion, including covert coercion imposed with a soft voice and loving words, is deeply disconnecting, and it certainly does not feel compassionate to the person on the sharp end. What seems to be called ‘Self-led parenting’ is a far cry from the deeply respectful, non-coercive spirit of the Self of IFS when they are talking about adults.
When you struggle against or take a coercive approach with another person, the natural response of that person is to defend their corner and fight back. The same happens inside our own minds. When you are fighting a part of your own mind, that causes the part you are trying to stamp out to dig in, to entrench itself, to defend its corner more vigorously.
Life can be messy for all of us. Sometimes when we try to make improvements, part of our mind panics, and that can hurt.