In which lines in this poem does the speaker compare her love to the pursuit of a social cause? sonnet 43

"I love thee freely, as men strive for right."

Men striving for right imply that a group of people (the social aspect) are working together to obtain a goal (strive for right). 

Many times a poetic line must be read out loud to understand what the person was trying to say. That would be a suggestion as you look at future poetry.