Why does wiring to a surge protective device need to avoid sharp bends?
Surges often approximate an &quot;infinite impulse&quot; and, as such, contain significant high-frequency components.  In order to be effective you want the surge protection device to shunt as much of that impulse as possible to ground so that it does what you installed it for, specifically to protect your equipment.
A bend of any kind in a transmission line affects its impedance and a sharp bend affects it significantly.  You might not think you are employing a t-line but considering the HF components of the surge, it is indeed one.
By keeping it as straight and short as possible you keep the impedance as constant as possible and therefore you reduce reflections which reduce the effectiveness of the surge protection device.