"women’s vagina isn’t meant to be penetrated at all, but only meant to expel a baby."
What the fuck?? What planet are you on, you crazy bitch?! Just how the hell do you think a baby would get in there?? Do you think we've had in-vitro fertilization and artificial insemination since the dawn of humanity?
Maybe your vagina isn't "meant" to be penetrated and heterosexual sex doesn't come natural to you, but that would be because you're either a lesbian or asexual. And that's perfectly fine, but most people have at least some if not exclusively heterosexual attractions, so "PIV" comes natural to them. Deal with it. Yeah, honestly, sometimes heterosexual sex seems kind of weird to me too, but I'm not heterosexual, and I still know there's nothing wrong with heterosexuality or heterosexual intercourse.
Patriarchy and all its disgusting cohortsmisogyny, male privilege, objectification, rape culture, etc.did not start because some guy stuck his penis in some gal's vagina. The fact that your vagina was biologically developed primarily for reproduction via coitus does not mean any of the things you've apparently associated with the idea: that fucking and baby-making are all women are good for, that women are obligated to make babies or have sex whenever their partner wants it, that rigid gender roles and male privilege are acceptable, or that rape and sexual objectification are ok. Hell, the value of a man can be similarly reduced to nothing more than a sperm bank if you think of people solely in terms of the function of their reproductive organs.
The notion that all penetration is "degrading" or "wrong" is the result of patriarchal culture incorrectly regarding: (1.) penetration as inherently feminine; (2.) femininity as degrading, inferior, and a sign of weakness and subservience; (3.) weakness or vulnerability itself as dehumanizing character flaws, which is already a very strongly misguided notion regardless of the fact that femininity is not a weakness or vulnerability in the first place; (4.) character flaws as a valid reason for dehumanization, which is similarly a very strongly misguided notion regardless of the fact that weakness and vulnerability are not character flaws in the first place; (5.) the value of females as being measured solely in terms of their sexual attractiveness, reproductive capacity, and other "usefulness" to men (i.e. the textbook definition of objectification), making them valid targets for rape and violence as a result of aforementioned dehumanization; (6.) and the systematic discrimination, violence, objectification, rape, and other injustices against those whom they oppress as a natural, acceptable, and deserved consequence of the perceived weakness that dehumanizes them.
I think that that pretty much covers the general gist of it and why I think you have some kind of internalized misogyny going on in that head of yours, but it's quite a bit of a simplification for the sake of brevity. This comment is already too longsorry for the length and choir-preaching, guys, but as a male who self-identifies as a feminist, who genuinely works to support gender equality and expose patriarchalism, male privilege, and misogyny for what it is and does, and who owns up to his male privilege and tries to offset it instead of denying it as though it were some kind of coupon one can choose to redeem or an offer one can decline, the posts on this particular site tend to really push my buttons and spark a nigh-insatiable urge to write passionate and lengthy responses. It feels weird and kind of hurts to be attacked by your own camp, even when it's only by a small, crazy, and out-of-touch fringe minority not representative of the whole.
Heterosexual sex is perfectly possible without objectification, degradation, dominance, or rape. All it takes is a clear establishment of mutual consent, mutual respect of personal boundaries and each other, and both partners regarding one another as equals and as human beings who are worth more than their physical attractiveness, sexual abilities, and willingness to "put out." But those things apply to virtually all sex, not just heterosexual sex.
In case the people on that site actually stumble upon this, here is some more reading for the crazy man-hating, male-phobic, and heterophobic people who identify as feminists:
TL;DR: Feminism, you're doing it so very wrong.