"Where do you draw the line?" is almost always a trivial rephrasing of the slippery slope fallacy. We live in a world where there are no lines, and we draw them in arbitrary places so that we can make the world work. If that bothers you, you are just going to have to adjust your worldview to be compatible with the reality you were born into.
As far as I can see, the two concepts have no bearing on each other whatsoever, but in any case, I can't help you to understand how something doesn't imply something else. You're going to have to justify how it does imply that. You can start by defining "situational" and "relative".
