I think human sexuality is diverse in its feelings and expression. I don't accept that it is only "fluid" for women, and would wonder if that description comes from the need to justify the objectification and subjugation of women through sex (i.e. their sexuality is fluid, so it's "natural" for them to do things and have things done to them that would never be acceptable or "natural" for most men.)
Both women and men in our society ARE, however, conditioned to see women "naturally" as the objects of sex, not subjects. They "give" sex to other people. They have things "done to" them. Whether it's a man or men with a woman or two women together depicted in porn, the scene is designed for the male gaze. If women get turned on while watching, that's a "by product," and a beneficial one for the men who are the real targets of porn. That means those men will stand a greater chance of replicating what they see in porn - of being able to do to a real live woman what is depicted on screen. It's all for the pleasure and power of the man, not for the woman.
It is insightful that you say, Totoro, that you say, "with the porn, the women are almost like sex toys.. they look like fun to have sex with." Well, that's exactly what the makers of porn want those watching it to think. Companies spend billions marketing their products and services in just the same way.
In the case of vodka, zit cream or fast food, say, they want you to feel good about their product, want to induce you to buy it because it will make you feel good. They want to make money from selling you a good feeling.
In the case of porn, they want you to feel good about what you are seeing, want to induce you to keep clicking (which links to advertising revenue) and preferably, part with cash to consume more of their product. They want to make money from selling a good feeling as well.
But, of course that "good feeling" means getting across the message that sex as you see it in porn is normal, is natural, is good.
Zit cream makers don't want you to think how possible allergic reactions or how their chemicals damage the environment. Vodka distillers don't want you to think about the cost of excess drinking to society. Fast food purveyors don't want you to think of the risks their food pose to health or the suffering of battery farmed animals they use. If challenged on any of these things, they'll provide a swathe of "evidence" to show their products are perfectly safe (if used responsibly,) and people have a right to consume them if they want. Often, they'll be proactive in promoting how "safe" and "beneficial" their products are to counter any challenges that might arise.
It's no different from porn.
Alot of folks have bought the line from porn that "women are almost like sex toys . . . they look like fun to have sex with," which porn makers will insist is totally harmless. But, it doesn't take a genius to work out that this message reflects and reinforces widespread views about girls and women - views that are translated wider attitudes towards women, toward's women's sexuality, attitudes to justify the objectification of women, and attitudes that normalise sexual violence towards women.