*I am including spiders and other tiny animals people consider expendable and okay to exterminate without a care. It is justified with "they can't think or feel", but it is really because they are annoying, frightening, eat and seek shelter inconveniently, or just because they are small and easy to kill.
If you spend time with insects and watch them carry out their own business of living, you would be disingenuous and wilfully ignorant to insist they do not exercise decision-making or have preferences. If you can't be arsed to understand firsthand, at least read other people's work on the topic before holding forth that insects are vacant. Even with research, however, you or I cannot know with certainty if insects have an experience of pain or selfhood. It is unknowable and we can only guess based on observation and Trusting the Experts.
If you guess wrong and therefore feel entitled to accumulate, manipulate, and destroy them as you would objects, then... actually you've partaken in a self-serving leap of logic. Much of insect sentience/awareness/"intelligence" discourse takes a loaded premise for granted and claims a pro-capitalist conclusion as unavoidable when it isn't.
The unexamined premise: insects have no internal experience worth considering when we make decisions that impact their lives.
The desired illogical conclusion: it is permissible to process insects and features of their habitats in service of any human desire, in a limitless fashion, with complete disregard for the effects on insect lives (e.g.: loss of freedom of movement, mutilation of the body, the deprivation of one's own singular life).
However, proving insect cognitive abilities with industrial science doesn't protect anyone. It shifts the goalposts. Some types of bodies and life forms will always be too stupid, too incapable, too lacking in awareness to *not* exploit. It is not really crucial to know definitively whether insects meet some asshole or another's criteria for consciousness and ethical consideration. We don't actually need to subject more insects to experiments of confinement and torture to move on with life and let insects live theirs. It is pretty urgent that we leave them the fuck alone, for everyone's sake. This is easy to do right now, in advance of further experimentation and study.