I think some people don't like utilitarianism because it leads to questioning some moral assumptions which intuitively seems obvious or ever taboo to them.
But it is actually good to questioning it, people was ok with slavery in the past, racism, etc…, and now they are ok with thing like industrial farming.
But it should be very clear that the moral framework doesn't allow you to always get the correct moral practical positions, no moral framework can do this.
So on the specific positions :

> This is why EA leads people to believe that hoarding money for interstellar colonization is more important than feeding the poor,

People can believe this without being utilitarians, and I think it is false on an utilitarian point of view.
1) We have all the time in the world for interstellar colonization as long as we don't mess up very badly.
And if we mess up with AI, interstellar colonization doesn't even help.
2) Also we are very very far to be able to do interstellar colonization, and if we could now, I think it would actually be bad.
3) Fixing our earth problems is much easier than interstellar colonization, and will help to have more time to do it, and to make it more probable it would be a good thing, so it is obviously the priority.

Wanting space colonization seems more like having to do with a very motivated reasoning because people like science fiction. (and I think the same thing about wanting to go on the moon again, and a lot of space projects)

> why researching EA leads you to debates about how sentient termites are

Do you think there is some probability that they are sentient ?
If not, then you think these people are wrong about facts, not about their moral system, they are researching something you think are obviously false.
But if termites are actually sentient, isn't it very important to know ? Or should will not care about them being sentient because, what, they are small ?

Not sure I understand the thinking behind your repudiation of Utilitarianism. I am also not sure how likely I think it is you update.

This is why EA leads people to believe that hoarding money for interstellar colonization is more important than feeding the poor,

But EA's are doing more to help the poor and prevent X risk than 99.999% of the population

why researching EA leads you to debates about how sentient termites are

This seems like a totally relevant fact to investigate. Humanities moral circle is clearly not well thought-out. This is just a rudictio ad absurdium (the above is too imo).