You thought wrong, but you are not alone in your thinking. It is definitely 'hear, hear' as in listen - what this man is saying is worth listening to
https://grammarist.com/spelling/hear-hear/
I've always thought it was hear, hear, which originated, I think, in the House of Commons. As mentioned earlier, MP's would agree with some speakers by shouting Hear, Hear, meaning, as stated earlier, Hear him, Hear him.