I have been involved in patent litigation for many large companies, in a defensive role. And while some do blatantly violate patents, they generally go out of their way to work around the patent.
And there are some oft-requested features that don't exist in very popular products that don't exist solely due to patents.
And even patent trolls attack large companies more.
I just don't think that if you're a startup company you have much rational reason to care about patents. And if you do fear them, I suspect you'll likely fail due to that fact I doubt you're very rational.
I've heard of other similar incidents as well. They're far more likely if you're going into an existing market against well-funded (and shameless) incumbents than it is if you're in a nice market.
You're correct that the rational response is to not worry about it, simply because there's nothing you can do about it as a software startup. If someone wants to sue you, they will, no matter how far you go out of your way to avoid violating patents. So you just kind of hope you don't get unlucky and get sued before the company becomes big enough to file their own patents for defensive purposes.
Just because something happens infrequently doesn't mean it's not a real problem.
Again, I'm not saying it doesn't happen at all. But so do random bits flipping due to cosmic rays, but I don't think we should change how we write code due to it. Something are sufficiently rare that they're not worth spending much time on.
I can't really get into any specifics of the litigation because it's still ongoing.