Normally people shouldn't care, because it shouldn't matter. But the reality of the situation is that Hunter is so intertwined with the "big guy" when it comes to shady deals, influence peddling, etc., that he cannot be removed from the conversation.
Hunter was a big part of the last election... well, actually not, which is what made him an even bigger part of the last election. His absence was palpable, and his absence was manufactured by the left through censorship and deliberate cover-up in their 24x7x4 efforts to get rid of Trump.
So if Hunter was just the run of the mill rich kid who turned crackhead and had an illegitimate daughter with a stripper, I couldn't find the energy to give one single fcuk. But that's not how it is, so anyone who cares about Joe not being susceptible to blackmail, etc., has to care. I bet the FBI has all kinds of influence with Joe nowadays (since they've got the laptop.)