Well, I don't fully understand whether there is a disagreement among you people, or whether you are joking (I'm not an English speaker).
The fact that it says "Choose one" does not exclude looking at the top card, it has nothing to do. Neither has nothing to do the word "or".
Yes, it does.
The structure of the card text is as follows:
Choose one: x, or y.
Thus, you have two options. You can do all of x, beginning to end; or you can do all of y, beginning to end.
'x' is:
Set aside the top card of your deck face down on your Native Village mat
That does not say you can look at the card before setting it aside, therefore choosing this option does not give you the right to look at the card at the start. In much the same way that you cannot gain a Province before setting the card aside.
'y' is:
put all the cards from the mat into your hand.
That also does not say you can look at the card, therefore you can't.
In neither case are you given the right, therefore you don't have the right.
Now, there is a part that says you can look at cards that are
already on the mat. But that means, in order to look at the card, you must first have already placed it on the mat. That means you have already done x. It is now too late to change your mind and do y, because you have finished playing the card.
There is absolutely nothing about Dominion rules that is "deliberately left open to interpretation". Dominion is a game that expects you to be able to follow card instructions to the letter, very precisely. If it's not mentioned in the rules FAQ, it's because DXV never imagined that somebody could really imagine things to work the way you think they do.