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.
Eh, being mentally prepared for his sudden departure in Season 2 is not the worst thing. This isn't something he writers intended as a plot twist after all.
Talking about a show that aired 30 years ago isn't "spoilers". Anyone who wanted to not be spoiled has had plenty of time to go rectify that situation by now.
At some point there needs to be a statute of limitations on this stuff. In general I find spoiler fanatics kind of silly anyways: if I don't want something spoiled I don't read online discourse about that thing. It's my responsibility. But whatever.
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.