Why the resistance to advocating for humane options if you can't quite convince someone to go vegan?

So, I get 'humane washing' is a thing, absolutely, but that doesn't mean there are not credible institutions that put effort into making sure their certifications means something.^*

I also understand that the goal of veganism is top stop exploitation and cruelty and to end the commodity status of animals, and that pushing for humane alternatives is at odds with that. If that's where people draw the line, fine, I guess.

It would seem to me, though, that if you can get someone to care somewhat about animal welfare but not go vegan, there is a chance you could get them to at least buy humane options, which surely is a huge step up and better than no reduction in suffering at all?

This Kurzgesagt video has a good overview of the difference spending a little more for humane alternatives can make in the lives of the animals being consumed. Is that not worth fighting and advocating for, even if it's just as a secondary fallback position?

Is denying that option outright in every case honestly better for the animals, or is it only better for the vegans meant to be arguing on their behalf?

Edit: based on replies, a good question might be: Are vegans inherently fundamentalist, and if so does that do more harm than good?

^{*People wanting to debate semantics and argue about the term 'humane' as opposed to addressing the substance of the argument will not be responded to.}