I think the confusion around the word bug is a specific problem among English speaking people. While the word "bug" is legit term for a whole family of insects, its also used commonly for basically all - and mainly unwanted - insects in general.
In German for example we don't have that problem really. The german word for "bug" (real bugs) is "Wanze", while beetles are "Käfer". It's not common to call all insects "Wanze" here.
RE: Little guide to avoid typical mistakes when determining insects and other arthropods.