Going back to your original question, unfortunately, you would certainly be liable (insurance wise) for damaging a moored boat in this situation.
It would be deemed as an avoidable accident.
Very frustrating but it's one of those many situations where you are virtually powerless without CRT and/or police assistance.
It sounds like, even if it did move on, another might replace it and so the situation goes on, so maybe relocating would be the best option for a stress free life.
Will your boat not come out at all or is it just really awkward?