They can't base payroll on one anomalous day. As has been mentioned, aren't flex hours something that can be worked out if stores are over sales over time? One day over sales, they can't count on that enough to boost hours overall, but if a pattern emerges, yeah.
So, if Target doesn't cut any hours in January and they spend 300% (or 500% or whatever) more on payroll than they see in profit, how, exactly, does that benefit workers? So far, my store seems to be decently staffed. We haven't had to have HL backing up the lanes more than we did during the season. Backroom is empty. Floor looks good. Electronics could use another person, for sure, but the losses on those areas might convince corporate not to cut trained electronics hours, but overall my store is doing what needs to be done with the hours they have, and hiring more.
You're assuming the only reason they cut hours is to fuck workers, and that's just not the case. If they staffed my store the way they did on Dec. 23 they'd have a lot of people sitting around doing nothing, pushing the store into the red and putting everyone's job in jeopardy. How does that make sense?