You are assuming that it is a big fuck up that affects a lot of units and/or people, and that the way a phone is held usually doesn't affect its reception. You are also implying that the iPhone 4 antenna has worse performance than its predecessors. Neither of these things are conclusive, and some reports suggest the opposite.
Hypothetically, what if these things aren't true, then what would be the appropriate Apple response?
"We have reasons to believe these reports aren't true and that in fact the antenna is better than in the previous versions; nevertheless we are taking steps to investigate this issue"
There, is that so hard? ... No, telling a customer to not hold it like that is not acceptable ... WTF is Jobs smoking? Fortunately for him these news have a closed circuit, as only technically inclined people have an interest in such things; nevertheless ... what if it's a real problem with those phones and it turns out to upset lots of regular people?
Hypothetically, what if these things aren't true, then what would be the appropriate Apple response?