Sorry you saying this doesn't make it true. I've been accidentally spoiled and not given a shit and been intentionally spoiled and been annoyed at that person.
So if people saying they don't care about spoilers care about spoilers why would they say it in the first place? It's always code for not caring about a certain way people get spoiled or not caring if someone else gets spoiled, it's never not caring about spoilers in general.
If you don't want people implying that you're insane, don't say insane things.
Ten feet is not far. At a normal voice level you're still well within the clearly audible range at ten feet.
If you're complaining about hearing someone ten feet away, you're complaining about reality.
And that's not getting into your utterly bizarre free speech argument. Which honestly is just too inane for me to respond to and will only lead to circular arguments. (i.e. your criticism isn't exempt from criticism, etc, etc)
If you're talking loud enough that people can hear you ten feet away in a crowded canteen then you're talking too loudly. Even then, what arbitrary distance is OK? Fifteen feet? 30 feet? It's not possible to make everyone not hear you, but in most situations you can lower your voice without ruining the conversation you're in.
As for the free speech thing, it isn't asinine seeing as both you and others don't want to be policed whilst also want to police others. People have the right to complain, saying they shouldn't unless they get spoiled under somr arbitrary parametres is policing what they can and can't say.
Again, thanks for calling me insane.
Lol, take the L. How about the person who overheard grow up a bit? Its not at all reasonable to walk up to two strangers having a conversation and telling them they spoiled it and demand an apology. I would seriously laugh at someone if they did that.
Complaining about someone talking loudly on a message board isn't the same as what you suggested, nor is asking a co-worker to quieten down a bit when talking about GoT spoilers. Again, this entire conversation started because people saw someone complaining about a random stranger talking loudly as something worthy of argument, that's what I mean by "taking the L." You don't have to listen to the guy, you don't have to care, I'm just asking you to be a little empathetic and not actively decry them for feeling the way they do. If you think what they're getting annoyed about is too extreme then explain to them why it's not a spoiler instead of going "OMG SPOILER CULTURE STRIKES AGAIN."