> a bad feeling caused by knowing or thinking that you have done something bad or wrong
Here it is from Cambridge:
> Guilt is also a feeling of anxiety or unhappiness that you have done something immoral or wrong, such as causing harm to another person: She was tormented by feelings of guilt after putting her mother in a nursing home.
There is no requirement that things could have gone differently, or that if they could have gone differently a different outcome would have been better.
Your definition is not compatible with this, or even related to this. You've stated fairly clearly that you don't believe guilt exists. That's odd, but defensible. (Though trust me, you're wrong.) Pretending it means something other than what everyone but you thinks it means isn't defensible.
> Feel free to propose an absolute version of right and wrong, to me it seems like an impossible task
I didn't say there was an absolute definition of right and wrong. I said there are people who conceive of the world this way, and that's true; they are quite numerous. By weakening to just the idea that certain actions in a definite fixed context could be correctly labeled "right" or "wrong", you pick up many, many more believers, practically the entire world.