Because you are then passing the array  @fred to the function print as an argument list; the array is evaluated in list context and yields its individual elements.

Update: E.g.:

c:\@Work\Perl>perl -wMstrict -e
"sub foo {
   print $_[1];
   print qq{\n};
   ;;
   my @copy_of_arguments = @_;
   print $copy_of_arguments[1];
   print qq{\n};
   }
 ;;
 my @ra = qw(one two three);
 foo(@ra);
 ;;
 foo('four', 'five', 'six');
"
two
two
five
five
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See  @_ in perlvar.