Then what hope do you have with a 2000 yr old manuscript from an entirely different culture? If it contains such idioms then you're, at best, guessing what is really meant.

You read everything in context. But I think you know that. Jesus didn't literally hate His family, so when He tells you to, you can surmise a lot from the text.

It seems most fundamentalists take is as-written on the assumption that such cultural elements are not there.

I'm not a fundamentalist, but I do think you can read the words, look at the body of work about Christ, and make strong inferences.
I don't think this one is a brain tickler. I just don't.
Ray