You probably still have a >50% chance that it's going to be over water since that's the direction it was initially moving. Yes, if flight termination fails and by chance it vectors backwards towards land somehow without just spinning like out of control rockets normally do then it may fly far enough to wind up on someone else's property but that's why launch sites are located at a reasonable distance from inhabited areas. The point is that it's very different to take all of those precautions vs. just flying your rockets over inhabited areas as a matter of course and not giving a fuck if they land on someone.
In general I agree with the point you are making, but if you will indulge my "well actually..."
From to the Range Commanders Council Range Safety Group, 2010, summary of FTS requirements:
2. produce a small number of pieces, all of which are unstable and impact within a small footprint;
And also another requirement relevant to this particular video where the spent booster clearly had uncombusted carcinogenic hypergolic fuel when it hit the ground:
3. control disposition of hazardous materials (burning propellant, toxic materials, radioactive materials, ordnance, etc.);
