I think you've slightly confused it. It's trying to warn you against doing
post = Post.find params[:id]
if post.user == current_user
...
end
Because it's better to do
current_user.posts.find(params[:id])
Which doesn't apply in your case because it's users you are fetching, not some collection that belongs to a user. I'm not sure why you're bothering with the id parameter at all - why not
@user = current_user
?
Fred