@Hurray
My question on whether you are following your ancestral rituals was targetted to those who have claimed the authority to dictate how Tihar was done and should be done.

I understand your POV. I also don't like seeing things bluntly copied. But then I wonder whether that is necessarily a bad thing or not. Lets put the argument that you have the freedom to chose how you want to celebrate your festival aside. Let's look at it from cultural longevity standpoint. We could chose to continue doing something exactly the way it was done or we can improvise it a little bit and make it more suitable to how we like it. That's how I see Rangoli. Rangoli is not Tihar nor is it replacing Tihar. If it is made a part of what we do in Tihar, why not? If it brings family together (see Junglebook's post), why not? If it makes us happy, why not? Besides, isn't culture and ritual all created from the society? Why can't society modify/enhance it?

You brought up a point about Halloween. Should we start criticizing people who celebrate Halloween or Thanksgiving now?

One last thing, Rangoli not a novel concept. Decorating the entrance was always part of Tihar. It just got "enhanced" more now, via Rangol