No, the LH SOP is not against visual approaches is about maintaining visual separation , 2 different things. LH SOP said only in daylight, so Capt has no discretion here but to follow his SOP.
Monday morning Armchair quarterbacking here purely in the interest of learning and avoiding a situation like this in future.
Most airline SOPS have a statement written within something along the lines of-The Captain has the discretion to amend/ignore/adjust the SOPS if she/he feels it is in the interest of safety.
I feel in this instance perhaps if they had just accepted the approach and landed and then submitted a Safety Report to their Company with the reasons why they did it-Much safer to land at a familiar airport, diverting is making a long day to begin with even longer and more fatiguing, zero chance of pax aggravation issues if they land at their destination...the list goes on.
At the end of the day LH would want their paying passengers in SFO not OAK. So, if it is safe-go against the SOPS (as we all have on rare occasions), file a report, so there is a written record, have those tea and biscuits with the Chief Pilot (he'll probably give you a minor bollocking, and then quietly thank you for landing at the filed destination), discuss changes to the Company's visual approach procedures, and move on to your next flight.