while you are right, but only when building your own engines out of skyscrapers. what I said was in reference to a particular block and design that has set dimensions. If you change out the crank on a block for one with a longer throw you would need shorter connecting rods otherwise the pistons would be kissing your valve cover... not literally but definitely there would be contact between the piston and the head if the rod length is not changed.
So yes, the rod does not define the stroke of the engine. But rather the crank throw and the block define the rod. So if the crank changes, but the block stays the same, then the rod needs to change too.
honestly I don't know why I brought it up. I completely misunderstood what they were talking about at the time, I must of finished an overnight shift before I posted and didn't read it correctly