800k actually is small enough to give away when you're dealing at that scale. The lawyers fees and other fees wouldn't even be worth that much from a sale.
The bigger reason is reputation. If Techcrunch posted an article saying, founder screwed out of acquisition by billion dollar VC, it wouldn't work out so well for the next founder considering that VC.
Why would they just want their original investment back? They'd demand 5 or 10x the original amount (as VCs) which completely wipes out the acquisition.
That is incorrect, VCs absolutely have preferential shares with liquidation preferences which can be multiples of their returns. Some money is not really better than no money if their reputation comes out as nickel and diming their founders, and future founders don't want to take their money, and if the VC misses out on a big exit as a result, now the VC has lost potentially much more than getting the 800k back.
