If you block an exit in a way which angers founders/employees, even if you have a higher expected return on that particular deal in doing that, you're now going to be "that fucking asshole VC who blocked our sale" every day until the company gets a 100x return above what the deal would have been (which is probably...never).
Not only will the founders hate you forever (both your firm and you personally, the partner); employees of that firm will hate you, and anyone those founders/employees talk to. Also earlier-stage investors/angels in the deal will also likely hate you for being "that asshole late stage investor who tanked our deal."
As a professional investor managing a large pool of other people's money, you probably have the greatest risk tolerance and most diversification of anyone involved in the deal. For employees, founders, and even angel investors, even a 2-5x exit, if it's the best/most likely thing, is probably going to be life-changing in a positive way.