I saw a documentary about these countries (Kyrghistan, Tadjikistan, Uzbekistan...)

All the people who were interviewed were able to speak Russian and they seemed to like Russia a lot!
They were making lots of positive comments about being part of the USSR in the past. They explained the economic and moral decline that their countries had experienced since becoming independent. Criminality seems to be out of control.

Bear in mind that this was a British made documentary... If anybody had said anything bad about Russia, this would absolutely have been included. But all those interviewed were positive.... I also remember from school that these countries were literally built up from being very backwards places, by resources and expertise from Russia.

I don't know much about this region but I was sad to see the economic decline and the poverty of the people. It seems that lots and lots of people from there travel to Russia for seasonal work anyway. So they are not truly independent..

So my question is: Why exactly did these countries become independent?
If they like Russia and they are better off economically if they stick with Russia, then why did they leave? Or did Russia somehow throw them out of the federation?