Because that statement has no other meaning at this time and context.
Saying a choice was inherently dangerous, when the context of the conversation is someone making that choice subsequently being killed by someone else. Comes with the implication, stated or otherwise, that the initial choice shouldn't have been made. IE that choice allowed the outcome to happen. That's the very definition of assigning responsibility, ie blame, to the victim.
There is no other reason to point out that riding a bike is dangerous at this time. Other than to imply that the Gaudreaus should have known better.