The answer is a bc of the conversation he had with his dad
You didn't provide the excerpt, so i can only say what he thought about it and then you can fit it in. Emerson was a transcendentalist and believed in the good found in men and had similar thoughts. He believed, like many others, that we are innately good but the society corrupts us, because it doesn't understand true and gentle souls.
I think it's man vs society
The thing that is similar about the love that is expressed in "That I did always love" and "'Why do I love' You, Sir?" is the eternal kind of love that exists. In both poems, love manages to survive no matter what the circumstances are. Love has never faded whatever happens.