What's phallic about bullets?
Are women not allowed to be interested in small arms? The Soviet Union deployed women as snipers to great effect in World War II, and the idea that only men could be violent and warlike is itself gender-biased to those who look at history.
This isn't very complicated or contentious from any angle I can imagine. Unless you're coming in with an agenda, and take offense to the idea that certain types of games might be traditionally male-oriented.
If bullets are "phallic" (despite rarely even having in-game models) then portals are "vaginal" and the primary game mechanic is to have your player "penetrate" them.
In reality, all of this is just pseudo-intellectual Freudian bullshit.