First off there is nothing wrong with "a person that":
Pronouns for People and Animals: "Who" or "That"?
You are not an authority, you should at least look up your claims when it comes to the English language.
You're wrong. I am an authority. I should also point out the irony of a person correcting someone's grammar in run-on sentences.
You may not grasp this explanation, and that's fine. I'm going to make it anyway and just leave you to understand or not.
Let's take a simple sentence:
That red thing over there is the sweater of a girl
that I saw yesterday.
What did the speaker see yesterday? Was it the sweater or the girl?
Educated people will reason that the person is referring to the sweater because, after all, he would have used who to refer to the person whereas perhaps the context will lead the person to believe that he must be referring to the girl.
Of course, the entire problem is solved if the speaker simply uses the word
who.
Even more egregious, daily I hear sentences such as this one:
Karen is a girl from New York that I met at NYU.
By context, the person probably means
who but the word
that is directly connected to New York, leading to ambiguity.
Now you may argue that the sentence you used contained no ambiguity. Granted. However, it's bad form. It's like someone pointing a gun at his face and pulling the trigger. Maybe, it doesn't go off because it's not loaded. Fine. It's still bad form.
Second you earlier put down Wikipedia, we were not discussing wiktionary. Wikipedia is put together by volunteers, usually well educated and their work is continually checked. When fact checked Wikipedia is very reliable. It is checked far more often than Random House checks their work. Your standards are inconsistent. And dictionaries are notoriously unreliable when it comes to certain terms. Their scientific terms are wrong quite often, but that is because they give the common usage of words, which is frequently wrong when one is using terms on a scientific basis.
So now you're comparing Wikipedia to Random House dictionary? You
do realize that these things are not really comparable, don't you?