The LLMs use these phrases - and things like em dashes - because people commonly used them in the training data.

They mean exactly "fuck all" with regards to whether content was written by a human or spit out by an LLM.

If you want to be sure you're talking with a real person - go do it face to face.

Otherwise... let it go. Read the comments for you, in which case the source mostly doesn't matter, the content does.