Since the sharing_add_footer is hooked inside the sharing_display function, that is itself hooked into the_content, you need to remove_action later. This worked for me:
function jetpackme_rm_share_scripts() {
remove_action( 'wp_footer', 'sharing_add_footer' );
}
add_action( 'loop_end', 'jetpackme_rm_share_scripts' );