therefore some abbatoirs must be non-stun
Well - there some people who want there to be non-stun abattoirs.
But if there are, that doesn't meet my needs - which is to know that animals are not having their throats slit, fully sentient.
Why does an outdated set of cultural practices, attached to a religion, take precedence over that?
Why is it my values that have to be compromised, not those of certain Muslims and Jews?
Incidentally, I'm as woolly liberal as you get, so I'm sort of uncomfortable hearing myself saying this. But I think the fact that we bend over backwards to accommodate all creeds, means we don't stand up for the things we think are right.