Crutches in the natural are things we use when we are injured or lacking strength, usually while waiting for some part of our anatomy to heal.
Spiritually we use crutches to support ourselves in areas that are weak and that have not yet been given over to God for healing.
An example would be rebellion, when we are confronted with a leader who hurts us or uses authority abusively, we rebel instead of asking God to comfort us and then using the biblical approach of “pray for your leaders”. It might feel good but ultimately leads to our own fall.
Another example would be bitterness, a person’s bad actions or words seem to justify our holding a grudge, so instead of turning to God for healing and the strength to forgive (because it does take strength), we deal with it by suppressing our pain with self justification and give up our authority to forgive to the spirit of bitterness.
God’s idea is to heal us and strengthen us in our area of weakness, not for us to use a demonic crutch for years on end.
What we make agreement with has authority over us.
See also Authority and gateways and Unforgiveness & Justice