I agree completely with no going back after drawing cards. But when it comes to the "NOTE", Why would it not be allowed to take back Erase before cards are drawn?
My understanding is that the note is about the situation where:
1. You played Erase
2. You drew 2 cards but didn't look at them yet (maybe your hand is face down and you put them on top of it)
3. You now want to take back your Erase and put the cards back
Rules say NOPE.