1. You don't know if the receiver took insufficent care according to their view. Maybe they consciously accepted a tradeoff because they directed their attention on something else.
2. Maybe a reasonable observer before the fact would have said they were taking the appropriate level of care, but shit just happened.
3. Maybe they don't consider whatever happened a problem. Maybe they don't want to draw attention to it and just want to move on.
4. As advice, it's 100% based on hindsight. Where were you when the person made the decision to take whatever level of care they took? Where was your advice as they were taking whatever action they took?
5. It's unsolicited, extremely unspecific advice and offers zero insight. What other thing should they have taken less care with?