You should delete the spoilers. O'Hare's personal history is important, but the part of the comment about his chronological appearances in the show is not.
Unless they're a young person hearing about this show for the first time, here.
It's wildly unkind to suggest that just because you know the big plot twists, everyone else should as well.
But let's suppose I *did* care about spoilers. I shouldn't be expecting everyone to walk on eggshells when they're discussing Gunsmoke or Happy Days.