The biggest issue when it comes to this whole topic are asshole, grumpy men who straight up brag about pumping and dumping and manipulating women. That's just being a dick, and it's pathetic. Manipulative players like that do exist and women have every reason to be pissed at them.

Aside from that, there is nothing wrong with having sex with someone and then deciding to break things off. In fact, the default way women date is: "I'm currently interested in this person, let's see where it goes". That's it. That should be the default attitude of everyone about dating, both genders, men should just adopt that. There is literally no reason to elaborate: you can break things off with someone you are dating for simply not feeling it anymore. The whole premise of promising someone exclusivity straight away is just kind of silly, because we just... can't for sure. That's not how dating works.

It's not unheard of that women break things off with men after the first date, after the second date, after the first time they have sex, after two months, after half a year, after several years, not because anything dramatic but mainly because they are not feeling it after all. Happens all the time. Nobody really moralizes that, at least definitely not women.

I still remember this post I have seen a while ago which imo is a good example of how different we see this depending on people's gender. It was a dude talking about how it keeps happening to him that he dates women for a few months, seemingly everything is going great, the women express enthusiasm to meet with him again, and then they ghost him. Maybe 2-3 months in. And he asked advice for that, why it could be happening. Pretty much nobody in the comments even considered thinking about these women's character, rather it was all about "what's wrong with him", which is sort of understandable. But I'm certain that in the gender flipped version of the same post, the comments would have looked quite different.

One aspect is perhaps that men are more into having sex with a woman even if they already kind of sense that they wouldn't really want a long term relationship with her, and again, men definitely have the capacity to be shitty with that. But ultimately, there is no reason to elaborate about that in the dating phase. In a sense, it does not make a difference. Women's feeling of spark simply fluctuates and all they do is just follow it, which they should be free to do. That's quite literally it, they aren't doing anything fundamentally different than men. Think of men's feelings of attraction as more than one dimensional in this sense and it being possible for men to be "half-into" someone, I guess more so than it is for women. Ok, and? Men shouldn't deliberately be dicks, but ultimately we are not responsible for women's feelings about whether we are attracted to them or not, and to what degree. At the core, men simply follow their own "sparks" to the exact degree that it feels right. Just like what women do when they date. Sure, it can hurt women, just like how women's fluctuations can hurt men, because at the end off the day being broken up with after you thought something is developing and you were excited about it sucks. But the other person has their own internal experience of attraction which is ultimately theirs and they don't need some exact moral justification for it. So let's just leave it at that.

TLDR: men should stop with the grumpy asshole talk and attitude and simply stick with "I'm interested in you now, let's see where it goes". If men didn't elaborate and had the same type of pride in following their exact feelings like women have, no questions, then the whole pump and dump thing would simply have no basis of even coming up as a discussion.