That is not correct. They may postpone payment under a reservation of rights to investigate the fire. But if they can't prove the arson benefited the named insured they will have to pay the claim.
There is a old joke about the claims adjuster finding a gas can and a lighter in the burned out basement. He got really excited holding up the can saying "Arson!". The owner said, "Oh my goodness, somebody burned my business! Can I have my check now?"
