loads of people saying they love their mum unconditionally.
But that is because fundamentally they are nice/you have a good relationship.
If your parents/grandparents etc were to do something horrific, I do think that love would stop. Eg if your parents were to murder your kids.
Now, you may say (quite rightly) that they would never do that, but the point is, that there is an invisible condition on your love. The invisible condition is that they don't behave like a monster. If that condition were broken, then the love would (probably) stop.
If youhave a horribel mother, and chose to go non contact, bu still love you, that is not undconditional love, that is love where you have put boundaries in. By definition, as soon as you put a boundary in, it is no longer unconditional.
I think people are mistaking "I love them to pieces and would do anything for them" for unconditional love. It is not the same thing