It doesn't even matter if any of those are bugs/insects etc.
First of all the type names are not well chosen or specific enough and are more like common simple words that vaguely point in the right direction.
Secondly, bugs don't need to be Bug type, and non-bugs can be Bug types. (although so far there aren't any noteworthy cases yet, just "bugs" who are not Bug type: Drapion, Gligar, Flygon)
Its the same thing as with dragons. (They can be dragons without being Dragon type, or be Dragon type but not dragons. Kingdra is a nice example - and reverse: Charizard, Gyarados)
Types are a sum of abilities, features and strengths/weaknesses.
That is true for all of them, including the creature types.
Types are not "what kind of creature is this"
Types are not "where does this live"
Types are "what is this good at?"
First of all the type names are not well chosen or specific enough and are more like common simple words that vaguely point in the right direction.
Secondly, bugs don't need to be Bug type, and non-bugs can be Bug types. (although so far there aren't any noteworthy cases yet, just "bugs" who are not Bug type: Drapion, Gligar, Flygon)
Its the same thing as with dragons. (They can be dragons without being Dragon type, or be Dragon type but not dragons. Kingdra is a nice example - and reverse: Charizard, Gyarados)
Types are a sum of abilities, features and strengths/weaknesses.
That is true for all of them, including the creature types.
Types are not "what kind of creature is this"
Types are not "where does this live"
Types are "what is this good at?"