Part of their excuse for this exclusion is the claim the category "made to penetrate" includes incidents during which the perpetrator has forced the victim to use a body part other than his penis to penetrate the perpetrator's body part in order to sexually stimulate the perpetrator, and since the penetrating body parts aren't sexual in nature, the sexual violation of the victim is diminished.
These are the same groups which define it as rape when a woman is forced to sexually stimulate a man's penis with her mouth, a body part which is also not sexual in nature. They also define it as rape when a female victim is forcibly penetrated by a perpetrator's fingers, even though fingers aren't sexually stimulated.
They define a female victim as a victim of rape if the perpetrator engages her genitals in a sex act against her will, or if a male perpetrator engages her in a sex act with his genitals against her will. Excluded from this definition is when a female perpetrator engages her in a sex act with the perp's genitals against the victim's will.
They define a male victim as a victim of rape only if a male perpetrator engages the victim in a sex act with the perp's genitals that involves penetrating the victim against his will. Excluded from this is any traditional sex act that engages the victim's genitals, and when a female perpetrator engages him in a sex act with her genitals against his will.
In other words, the definition isn't written to exclude behaviors that aren't significantly sexually imposing, invasive or traumatic, but specifically to minimize the number of female sex crime perpetrators who would be counted as rapists.
Another excuse feminists and their followers make for this discrepancy is the claim that including incidents of being forced to penetrate would make statistics inaccurate because that category would include males who were forced by a third party to penetrate other victims.
Let's take another look at that idea.
A third party forces two people to perform a sex act, and feminists only want to consider one of them a victim, because... ?
There really isn't an answer to that question which justifies considering one victim's experience rape, but not the other victim's experience. In fact, even if you consider the female experience of sexual assault to be a greater violation of bodily autonomy by reason of penetration, in this type of scenario, the male victim has the added horror of being forced to subject the female victim to that violation. In addition to feeling dominated and violated because he has been raped, he'd also have added to that pain a sense of responsibility for his co-victim's suffering, and being forced to commit what, if he's like most males, would be an evil act representing a violation of his most basic nature, as offering protection is one of the most basic ways in which a male human nurtures other humans, and being forced to hurt someone (especially someone he perceives as more vulnerable than himself) would feel fundamentally and deeply wrong.
It would be a horrifying experience.
It's dishonest to suggest that the horrifying experience of being forced to perform a sex act against one's will is not rape simply because one is male, or simply because there's another victim upon whom the experience is also inflicted. Tailoring one's ideological approach to sex crimes to exclude male victims of female perpetrators isn't rational, but it does suit feminism's predatory exploitation of proxy victim status in women, and it does suit their equally predatory exploitation of presumed perpetrator status in men. Female victimhood is most exploitable if women are seen as wholly innocent. Male perpetration is most exploitable if men are seen as solely guilty. Show that females aren't universally innocent, and males aren't commonly guilty, and you lose the basis upon which feminist organizations like NOW have lobbied for law and policy that discriminates against men, purportedly for the protection of women. You lose the basis upon which these groups have demanded grants and other funds dedicated to feminist-led initiatives, organizations, and services dedicated to female victims. You lose the feminist ability to use accusations of rape apology to try to shut down discussion about false accusations, and other men's issues related to discrimination against men in criminal court.
That's really where the bottom line is; it's not about the semantics feminists try to use to excuse their choice to exclude male victims of female perpetrators from the definition of the word "rape." It's about money, power, and influence, just as it is with every other area of feminist hypocrisy.