I think the 'children can't consent' concept generally works.
I think the 'animals can't consent' thing is a retroactive justification for what is either ick, or a religious hangover.
I've had female dogs on heat try to hump me. Is that not consent?
We don't get dogs permission before breeding them.
The concept of bodily autonomy for animals is basically non existent.
The argument was originally that it was 'unnatural' but gay rights put the nail in the coffin there. 'consent' sounds good, but it isn't what's going on. It's the same 'unnatural' position, without the intellectual honesty.
Problem for me is. I kind of agree with the current cultural position. But there's no actual framework around it, and I don't like arbitrary rules for arbitrary reasons.