As you claim that failure to interbreed doesn't indicate a species barrier, how do you show that people and chimps are not of the same kind?
So, again, what distinguishes one species or kind from another?
Your question was: "If two entities cannot interbreed, are they different species?"
I was only allowing that there can be other reasons that two entities (of the same species) could be unable to interbreed. Sorry didn't intend getting involved in semantics, just being cautious.
People are different from chimps and all other animals because we have a soul. I don't even want to think about what kind of experiments are going on to breed humans and animals. Ewwww!