I used to design wind turbines for a living. Any wind turbine made in the last fifteen years has the capability for remote shutdown. This is not an option, this is basic functionality.
Please can you share a source that explains your info?
I don't think it's right at all at least to any systemic level. It's because Finland has a load of nuclear (~50% of all generation esp after the EPR opened) and also a lot of wind power.
Nuclear is not well suited at all to being curtailed, I also suspect it would be worth paying negative prices to avoid it to a certain level - the French reactor cracking problems (earlier design though) are hypothesized from what I read to becaused by a lot of demand curtailment putting stress on the various metals as they heat and cool frequently because of reducing output.
This massively simplifies reality.
E.g. in Finland where I live we also have issues with negative power prices. A few years ago we had some really low prices. It turns out, a fair bit of wind power producers never opted to add to their windmills any remote shutdown possibility, nor did they have the ability to monitor prices and react to them automatically. I.e. they just kept generating no matter the price, and had offers in at the network level at the lowest permissable price.
Since then, when they lost a non-insignifcant amount of money by running at negative prices, they've started installing control electronics in windmills and building IT systems and prediction algorithms to be able to react to this.
In the EU it is not as simple as "turning off when the prices are negative" since producers offer a certain capacity to the grid in an auction system the day before. You have to predict the weather + overall demand and set your offer accordingly.