Rembrandt
the artist
Because you know one representative means you know all 435?
I'm assuming if you know one pretty much unknown one and come to the capitol to talk to her, then you're more politically aware than most and more likely than not are familiar with one of the most popular/talked about Republicans representatives. One that both Trump and Biden have talked about publicly.
But sure, what you're saying is far more likely and he had no idea who she was; rather than him knowing and assuming she wouldn't post a caption like that. I don't think he necessarily cares about taking photos with disliked people or even people who spew white supremacy and racism like Musk and Rogan.