Yes but...

That often leads a dirty game. Litigation, especially license and IP related litigation, is often all about the meta, the strategy games and ulterior or adjacent motives.

The legal action itself, with associated costs and stresses can be scarier than the judgment. Deterrence or establishing legal cases and such can be the motive. Legal costs can be driven up to strategically raise stakes. Etc. It's nice when occasionally the system can be used to settle disputes or do justice.

I also wonder about ChessBase’s financials. If the costs were too damaging then ChessBase might have to shut down which ultimately isn’t good for StockFish. It’s possible ChessBase will sadly lose many customers because of the GPL (though it shouldn’t be so) because some people in our industry and especially companies are allergic to it.

> If the costs were too damaging then ChessBase might have to shut down which ultimately isn’t good for StockFish.

Why not? It's not like ChessBase ever contributed anything to StockFish.

> It’s possible ChessBase will sadly lose many customers because of the GPL (though it shouldn’t be so) because some people in our industry and especially companies are allergic to it.

ChessBase sells B2C chess engines, not libraries. Their customer base is either pro-GPL or don't care about it.

Because maybe it’s validating as a project to know a large commercial entity uses your code? Maybe the exposure Stockfish gets if ChessBase complies with their requests is worth making sure they can continue to survive? Maybe Stockfish is delighted that their project reaches so many users and is focused on making sure that remains so?

Surprising to see, but seems to make for a better future relationship. It's a game.

Most probably a crap lawyer - 90% of "lawyers" posses a single skill - to convince the poor soul using their services, that such a "deal" is advantageous.