Catsup or Ketchup?

As if we're not contentious enough, some people can take issue over how to spell that universal condiment, ketchup/catsup. I've seen it both ways.

Further, when is it okay to use this red stuff, so as to use a neutral term not likely to ruffle anyone's feathers.

On hot dogs? Dirty Harry takes exception?

On scrambled eggs?

What about on French fries? Actually, A-1 sauce or barbecue sauce also works well.

And we have to also admit that the red stuff is useful for smothering the bad taste of some foods.