My DBro and I are both LC with our parents. My DH and his siblings are NC with their mum.
DBro and I have never explained to our parents why the relationship has got so bad. There are many cumulative reasons than one big issue, but we have both taken a very big step back for our own sanity. In reality this means that we are both barely civil to them, as we both find it so hard to act 'normal' around them.
I think we all pretend that things are fine (this is probably the point of LC) but it must be very confusing and upsetting. I don't expect that our parents have enough empathy or insight to consider that their actions are the cause of the rift. They probably blame DSIL, who is actually absolutely amazing 
I do sometimes wonder if it is more cruel to be LC than to make a clean break and be NC. Our parents do see mine and DBro's children, but not as much as they would like and never to look after them.
So I suppose I am asking why you chose to be LC rather than NC. Or, if someone is LC/NC with you then what is it like? Do you know why it happened?
TIA