I don't really have a dog in the fight, though I do own one Sig. But it's unlikely I'll buy another one, not because of this thread, or because I think Sig isn't a quality manufacturer, but because their offerings are usually just a bit pricier than what I care to spend. For what it's worth, my P229 is one of my favorite pistols, runs great, and I anticipate many years of happy shooting with it.
However, this discussion has been fascinating to me and some of my buddies. Sig is a well-known and well-regarded maker on par with if not on a higher level than Smith and Wesson or Ruger; at least among myself and my fellow shooters. But as one of my buddies noted, if this was a Ruger or a S&W, this would be a non-issue; they would've just fixed or replaced the gun a long time ago. And at least in Ruger's case, the fact that the gun was bought used would also be a non-issue. And Ruger doesn't even have a written warranty . . .
Anyway, for myself, it's a bit of a head-scratcher; I still think Sig is a quality manufacturer, but their 'apparent' stance on this seems a little 'nickel-and dime,' to me.