I got 100s of pages when looking for it as well. I did not find anything that said German fighters (manned aircraft, not V1s) were crashing because of collision with the cable that connected the balloon to the ground. The links you posted do not talk about it either.
I can speculate why Germans did not want to fight around the balloons. When maneuvering you don't want to accidentally hit one of the balloons, not the cables. Hitting a balloon would not necessarily bring down the plane either, it would depend on the structural integrate of the balloon, which part of the aircraft hit the balloon, the speed of impact, and the altitude bellow that can be used to recover.
The Dover incident deserves elaboration because it provided, in the words of Air Marshal Gossage, a clear indication of their [the Germans'] respect for the British balloon barrage. In an attempt to clear the balloons from Dover, the Germans launched a major effort in late August 1940. They destroyed 40 balloons but lost six aircraft in the process. Much to the Germans' chagrin, 34 new balloons appeared the very next day. Air Marshal Gossage commented on the action: The protective balloons still fly over Dover. The attack on the barrage has proved too costly. ... In general, major attacks on balloon barrages have ceased, the enemy having realized that the game is not worth the candle. The fact, however, that he hoped to destroy our balloons is in itself proof of the utility of the barrage. During the height of the Blitz, 102 aircraft struck cables, resulting in 66 crashed or forced landings.
out of this link,
http://www.worldwar-two.net/armamento/90/You have to take the time to read all the information.