rm misbehavior

[MR ZenWiz]

I can't believe I have to ask this.

I always thought that rm would only remove a directory if the -r
option was included on the command line, that it would refuse to
remove a directory otherwise.

Today I was cleaning off some files on a backup disk. I ran a command
to see if there were any duplicates, using locate to identify
duplicates (probably not the best idea). One of the entries it found
was a directory that held 62 files. That directory was sent to my rm
function, which is supposed to intercept inadvertent directory
deletion, but the function deleted the whole directory.

Here is the function:

rm ()
{
    typeset ln="no";
    for i in $*;
    do
        if [[ "$i" == "-f" || "$1" == "-fr" || "$1" == "-rf" ]]; then
            read -p "Are you SURE??? " ln && [[ "$ln" != "yes" ]] && return 1;
            RF="$i" && shift;
        fi;
    done;
    /usr/bin/rm -I -v --one-file-system --preserve-root=all $RF $*
}

I even created a temporary directory to check this, and it deleted the
whole directory with 'rm <dirname>' (using the above function).

I (now) know that the function is not quite correct (the parameter
handling is incorrect). However, if rm is given a list of paths that
include a directory, shouldn't it refuse to delete the directory
absent -f or -r?

Mighty confused here...

MRZ