The argument is that a company like Apple, instead of investing its cash pile itself, should return that money to its shareholders who will, collectively, better allocate their capital than Apple will. This is almost certainly true.

The company then has essentially two choices on how to return that money. It can pay dividends, which are taxed, or it can do stock buybacks, which are not taxed until investors choose to transact their holdings. Financially, for most investors, buybacks are better.

I'll also point out that buybacks don't obfuscate prices, but instead permanently change them. By reducing the equity outstanding, the equity remaining gets more valuable.