Sorry, buy backs are not stock manipulation. Let's step back from emotions and political skew. A company is able to take their capital and deploy it how they see fit. This can include purchasing percentage ownership of their company back from stockholders. Whether or not you agree doesn't make it manipulation in the general sense. It's just a way for a company to use their money.
Why do they repurchase the stock? In order to impact the stock's value (also known as manipulating it's value). That is the definition of stock manipulation. No emotions involved, no need for the passive aggressive attack that I'm somehow being emotional.
It's not just a way for a company to use their money. It is a company intentionally using funds for stock manipulation, many times by executives who directly benefit from said manipulation. Companies even take out loans purely to re-purchase stock.