I agree with what you are saying, but if you actually wanted to pit your defense against someone else's offense you would be in a league where someone of your town hall belongs. If you have enough DE to be zapped that much you are clearly TH8 or above. If you are TH8 or above you belong in crystal 3 or above. If you are in crystal 3 or above people will snipe you for the loot bonus very quickly and you will rarely be zapped. You are being zapped because you are spending your time in a league where you don't belong trying to rob bases that are too weak to defend themselves from you. In other words, you are not pitting your offense against defenses that have even a half-way decent chance of defending themselves against you, but rather trying to prey on the weak that stand no chance against you. The weak do what they can and what they can do is zap.
I realize it is not entirely your fault. You are in low leagues preying on town halls one level below you because your prey is down there attacking people one level below them. If all the TH8's and above were in crystal and above (and the TH7's hung out in gold 1) we could all get great league bonus on every attack and still get just as much loot from raiding as well. But everyone hangs out super low where the league bonuses are too terrible to be worth sniping for and the result is that people zap without even bothering to attack your TH because the league bonus is worthless.

