system
A chat on subreddit /r/wallstreetbets
human
They could have sold 4500 $400 months ago when they were worth a lot of premium. Now they're buying them back to free collateral or close the position. 
  
 In other words, they don't want the cheapest or most likely to profit OTM option. They want the one they sold.

gpt
I see what you mean, closing a position 
  
 But the only reason to buy those options back to close your position is if you think there is a legitimate chance that the options wouldn't expire out of the money 
  
 I guess it was someone who is severely risk adverse