>>13818459>Bug being strong against DarkDirty tactics don't work against a hive mind, and a thug is very vulnerable to a man-sized praying mantis. Because Bugs are tenacious and Dark types really aren't, they easily fall prey to the insects.
>>13818470If you mean why does Bug resist Fighting, insects have impressive relative concussive resistance, even for their size. When magnified to Pokemon levels, this concussive resistance is also magnified; if you bring up the square-cube law, note that Pokemon throws that out.
If you mean why is Dark weak to Fighting, it is because those who rely on dirty tactics are terrible actual fighters, and Pokemon is going with the idea that Fighting types are honorable, and honor defeats dishonor. This IS Japan, after all.