>>41832877BUG resisting fighting moves makes sense due to their alien body type, but not the other way around ( a sting is still a sting).
BUG resisting mental attacks makes sense due to their overly instinctive-simple and alien brains. BUGS defeating psychics? Unless there is some Japanese folklore meaning, like with the Dark type, then no.
No solid reasoning behind FAIRY resisting BUG, except fairies being the Forrest Guardians, I guess.
Why is GHOST resisting BUG? Maybe to avoid giving GHOST another immunity? ok.
So it seems there are clearly understandable ways to buff the BUG type, allowing to give it weakness to ICE.