@tedchoward in this case, it's not really that it's a big file (though it is big), it's that it's a (really) big single line.
Every editor is able to load it without too much trouble when it's been pretty printed and spread across a half million lines. Though only Neovim (of those I tested) can parse it and do syntax highlighting and such. VS Code disables parsing and pops a warning, but to its credit search and editing does work.
But, when on a single line loading it crashes VS Code.