Feedback signals have a source signal coming in, and in this case it shows a negative feedback. Negative feedback will give 180° negative response to that output. For a switching regulator or linear regulator, if the output voltage were tracking high, the designer would want the control loop to pull it low or negative feedback. If the designer ended up with positive feedback, if the output voltage stats to go, it will start to go higher and as a result one will have an unstable system that will tend to oscillate and it would not regulate the output very well, nor respond to transients.