All I watch is crime documentaries. All I watch are crime documentaries.
I mean, I know "is" refers to one and "are" is for multiple, but does the "All I watch" at the start mean "is" makes more sense, seeing as that's what comes first. I think it would make more sense using "are" if you said: "Crime documentaries are all that I watch". I know you could rephrase the sentence in question, but for the two I have mentioned, which one is correct?