Are we saying killing bugs for just being there is slightly bad? I could maybe, agree with you, but bloodsucking ones, like mosquitos, deserve to die if they are penetrating your skin and stealing your blood. That is an attack, I suppose.
Now some spiders, brown recluse, poisonous tarantulas and the like, may only attack you if you provoke them, but does that comfort you when there is a fatal disease giving spider close?
Finally, if we did leave nature to its course, you would surely see insectus/animals kill others that come into their territory. We have the same right.