If I write a computer program with a variable called isSuffering that I set to true, is it suffering?

(I have no idea how consciousness works, so in general, I can't answer these sorts of questions, but) in this case I feel extremely confident saying No, because the variable names in the source code of present-day computer programs can't affect what the program is actually doing.

humans, right now, who are spending time and effort to fight animal suffering should be spending their time and effort to fight human suffering instead

That doesn't follow if it turns out that preventing animal suffering is sufficiently cheap.