I rationally know that, but I can't bring myself to wilfully destroy life, even that of an insect, with the sole exception of if something is dangerous. So I can totally understand the reactions of those who don't have a high "everyday sadism" score.
Whether its sadism or not is independent of the experience of the bug, even if that question is meaningful. It depends on whether the person committing the act believes the bug is suffering, and whether they enjoy it on that basis or some other.
And since the question is open as to what the bug's experience is, there may also be a tendency for individuals to interpret their behaviours as being evidence of suffering or not depending on how sadistic they are. Non-sadists may tend to interpret the bug's behaviour in ways that suggest there isn't any experience of suffering. Sadists will do the opposite.
It's difficult to see what if any interesting issues the question of the bug's internal experience could bear on. It's our perception or imagination of that experience that would seem to be far more important in how the act should be classified for a given individual.
