That was the first time the SC supported the individual right which is not surprising given that the 5 conservatives who were in favor of that were Republicans following their party's agenda. None of the previous SC justices agreed with that. Why did the conservatives ignore the precedent? Because the gun right wasn't a major concern for the NRA until the 1970s. Heck, the NRA even supported some gun control laws after the assassinations of Martin Luther King, Jr., and Robert F Kennedy but its conservative members disagreed and booted out the board of directors at that time and replaced it with more extreme members. After that, the NRA becomes more and more extreme along with the Republican Party and the justices appointed by Republican presidents followed along.