Once a ferment has reached its natural final gravity its protective blanket of CO2 starts to diminish. Sulfites contribute an antioxidant chatacteristic, but that too diminishes. The bottom line: for a wine that is no longer fermenting & not yet bottled, the less exposure to oxygen the better.
There are specific reasons you expose a must to oxygen: to encourage the growth of yeast when the current S.G. is still above the 2/3 sugar depletion point; to try to offgas an overdose of k-meta; to try to offgas the rotten egg odor caused by hydrogen sulfide, H2S, that some ferments generate; part of the sherry making process; to make vinegar.
There are no reasons that I can think of when it comes to why you would want to purposely expose a wine to oxygen as you prepare for bottling.