Its easier to think IC2 exist in a vacuum rather than try to balance it taking in consideration the absurd amount of mods out there. Yes they are general methods to prevent other mods to interact with your mod, but they are just that, general. They are quite limited compared to specific methods for each mod, and general methods may also break some compatibility with other mods that you think its rather ok to have in your mod.
This is one, rather effective method, to approach minecraft modding. You also have the BTW approach of shunning yourself from forge to keep interaction with other mods to the minimum, keeping the "Purity" of your mod intact, or the TerraFirmaCraft approach in changing the basics of the game so much, that other mods barely affect anything at all.