Persona 3 Reload calls out "harem" players - in other words, those who opt for all-female companions.
The original Persona 3 featured some unique dialog when the player deliberately formed a party featuring exclusively women, aside from the male protagonist. Their female allies would essentially call out the player character for deliberately trying to form a "harem" - a group of women with which one man has a relationship with at the same time.
In Persona 3 Reload, that line of dialog is still very much alive and kicking. As you can see from the clip below, Yukari first notes that the player character has deliberately formed a group of all women, before Aigis notes that this basically constitutes a harem. Yukari, as you can probably imagine, isn't enthused at all with the idea, but surprisingly, Mitsuru is pretty chill with the whole thing.
Got the harem dialogue in P3R from r/PERSoNA
This dialog actually changed in Persona 3 Portable during the female protagonist's route. Yukari would once again note that the group was formed exclusively of women, but this time, Aigis would say that the entire thing was a bit of a "chick fest," rather than a harem.
Essentially, this feels Persona 3 Reload's way of calling out some of the hornier players out there. It's a little more chill than in Persona 5, which famously has a very literal way of tackling players who romance more than one character at once: its cast all gathers together and beats up the player character on Valentine's Day.
This isn't quite that level of callout, but it's still Persona 3 Reload's way of acknowledging that there are some very horny players out there, and perhaps they shouldn't have quite that attitude towards all their female friends at once. Yukari would probably beat the snot out of them.
Persona 3 Reload is the series' biggest-ever Steam launch, but there's still doubt among fans as to what constitutes the "definitive" version of the game.
