I personally just think that a remake of a game should contain ALL of the content of the previous version(s) of the game. It isn't just the female MC that's missing in this case - it's missing EVERYTHING from the Portable edition, as well as EVERYTHING from the FES edition, which altogether includes tons of new scenes, new Personas to summon, and an entire postgame chapter. Also of note, the female MC isn't just a model swap for the male MC - there's a pretty significant plot difference towards the endgame depending on which gender you choose at the start. Anyway, point is, there's a very not-insignificant amount of content, tens of hours of content potentially, that they're just deciding to not include in the remake.
Besides, this is Atlus, so there's a very good chance that they'll end up releasing an updated version of the remake in a few years to add the content, for full price.
Edit: Also, the Persona community has been divided for years over whether P3F or P3P is the better version of Persona 3. Each version has it's own strengths and weaknesses, so it's really hard to say either one is truly the definitive version of the game. Atlus had the opportunity to finally create a truly definitive version by combining the content from the two versions... and they simply chose not to. So fuck 'em.
I personally just think that a remake of a game should contain ALL of the content of the previous version(s) of the game. It isn't just the female MC that's missing in this case - it's missing EVERYTHING from the Portable edition, as well as EVERYTHING from the FES edition, which altogether includes tons of new scenes, new Personas to summon, and an entire postgame chapter. Also of note, the female MC isn't just a model swap for the male MC - there's a pretty significant plot difference towards the endgame depending on which gender you choose at the start. Anyway, point is, there's a very not-insignificant amount of content, tens of hours of content potentially, that they're just deciding to not include in the remake.
Besides, this is Atlus, so there's a very good chance that they'll end up releasing an updated version of the remake in a few years to add the content, for full price.