You don't have to be there for the case to go ahead, and for an injunction against you andyour product to be granted inside the US. It's not a "criminal" case, where they want to drag you there so they can punish you, it's a "civil" case where the other party wants to get their hands on your money.
It doesn't matter what country you live in, if you sell your product in the US (and who doesn't with digital content in english?), they can sue you in an american court.
Good luck with them dragging you from your home country to America, just to go to court. ;)
I don't think that would happen...
Sure, if you choose to visit the US in the future, it might be an issue.
Visa, Mastercard, Paypal, Steam: many of the companies that move money from your customers to you, exist in the US, which means your supply of money can be cut off, or redirected to this other party.
If you don't sell your game to American customers, and don't use any American middlemen, then it's not a problem... but almost everyone uses American finance, and the American market is one of the biggest for selling games...