And you were answered already. Making it in the beginning allows backers to decide based on the input. Making in the middle doesn't, it just makes it mandatory for those who paid before that goal was made (if the goal is reached of course). Quite basic, but many here somehow think it's OK to do that even if it happens that many backers find that goal wrong.

That's exactly how it works. Backers invest in the product. And as investors expect something from it. If they get not what they expect, it's wrong. Did backers who supported the project expect that their money will be used to pay for exFAT? No, why would they. And many didn't appreciate it when it was announced. Compare it to any other type of investment.