Reverse psychology at play.
If a pre-med adviser says you have no chance, but you got in, then you won’t hold a grunge long. Whereas if they say you will get in but you don’t then forever you will be angry.
Having said that, just keep in mind how many UG pre-med advisers actually went to Med School and keep that in perspective.
Jokes aside, most pre-med advisors are keenly aware of the stats and are openly honest with students who ask. But some people hear one in three and automatically thinks they are being told they are in the two who don’t get in.