Why instagram doesn't allow users to register using PC?

[Vladislav]

Hello, I have been searching a way to register on instagram using PC, without android or iPhone, but without any success. The only option is to install bluestack android emulator, but my PC has too old graphic card, and now I can't do anything.
So, because I would like to participate instagram and to follow some users and their photo uploads, I am so frustrated because I can't find any reasonable answer why instagram or actually now facebook like the owner of it, doesn't allow users to register without the android mobile phones of iPhone?
I would like to know the answer, no matter what that could be. Just to know, to calm down my mind.
If that is maybe the reason that previous owner of instagram have some deal with the manufacturers of android mobile phones, or iPhones, let it be, just would like to know if that is. Or if facebook have some deal with them, let it be, just would like to know if that is the reason.
If maybe the facebook is the owner of android platform , let it be, just give me please the answer.
In such situation, they are forcing us to buy android od iPhone, if we want to use instagram. So it must be some reasons in that way.
Or the last, maybe it is just simple their caprice .
I was thinking so much to find any reasonable answer and that's the only what I got in my mind.
Please, if there is anything more, answer.

Best regards, and thanks in advance.

Vladislav
I don't have any other posibilities to answer on these 3 new answers, but with this feature, so I would like to thank to participants at first, and to say that I am fully aware of lack of instagram etc, etc, but this is not what I have been asking. I know that I can use webstagram etc, sites for searching users and their photos, I read many times that Instagram crew is lazy etc, but my question was very specific. Why instagram doesn't allow users to register using PC? Simply any reasonable answer why they do not allow this feature.

[Luke]

My advice stay off Instagram. The developers are lazy and cant add decent features.

[Takmim Hasan]

Instagram themselves have released the Web Feed on their website. This allows you to like, comment and view photos from the people you are following. You cannot however upload photos, you still have to use the pc.