Indeed you did say that.
And unless I am mistaken, "does not need to" implies "can".
So if you say "the imagination does not need to defy the laws of physics..." then you are saying that the imagination can defy the laws of physics.
I do not.
If, as you have stated, the imaginer can choose whether to make use of the laws or not, you are again stating that the laws of physics can be defied through the act of imagining (including the selection of which laws to make irrelevant and/or defy).
So perhaps further clarification is in order from you to explain how you apparently get to claim that the product of imagination can defy the laws of physics, yet then claim that this is not what you said?
Try
The laws of physics do not apply to the product of the imagination, and can be considered as irrelevant except as inspiration.