While your agent is speaking to the listing agent they may also want to ask about seller concessions. If they did check the box intentionally perhaps they are trying to avoid them which would be a mistake in this market as they are unlikely to receive a full price offer regardless what loan program their buyers use.
It may be a typo. Some home owners do get alittle freaked out about FHA because they have this old thought that they're going to have to make repairs to the house. Becareful, because if they're really adamant about not wanting FHA they may have something to hide. Just a thought.