I don't find anything you said very convincing. You are simply characterizing a transaction as nefarious, and perhaps conspiratorial. Of course, there are incentives and perhaps even misincentives around such sales, but that doesn't mean they are inherently bad.
There are mechanisms that are commonly employed to REDUCE the price of the stock, (ie. a stock split), and nobody bats an eye about that. Buying back stocks is a reasonable way to employ cash reserves, and protects the firm from exposure to foreign exchange rate, and inflation risks.
I will agree with you that the way executive bonuses are structured can be a perverse incentive that borders on fraud. But blaming the buyback of stocks itself, isn't grounded in any inherent economic misdeed.