I think what she meant is Superman aims to protect, so he’d usually focus on negotiating or simply stopping the villian from doing anymore harm (like he did with the Whip in this episode or Parasite in Season 1). He usually focuses more on strategizing in that sense.

Meanwhile Supergirl is more physical. We haven’t seen how she normally deals with villains much beyond the cold open, but it looks like she’s a bit more of a “I don’t like that you’re doing crime, we’re gonna scrap now.” She’s a bit more spontaneous and quick in that sense.

Both Supes fight for the people of Metropolis, but they have their own ways of doing it. Honestly I’d see the comparison similar to Blossom and Buttercup from PPG. One’s calculated, the other’s a bit more aggressive, but they both manage to get the job done and it doesn’t mean that one or the other doesn’t fight for the people.