That’s a good example. You simply can’t grasp optimal choices or know possible events and outcomes before going through it a great deal of times, and it’s likely that you’ll get killed too fast to experience much if you start on normal. You definitely end up switching to normal as you improve, learn, and unlock, but it really benefits and smoothens the learning curve to start easier.
Happens to me a lot. I just refresh the page, try to vote again, and then it works