What?
Do they 'decide' or just sell to whoever's buying?
They had no need to put their prices up like they did. They didn't need to make the record breaking profits they have.
They chose to do that and at the same time they put thousands of lives at risk, adding untold debt and stress to already struggling, hard working people and even more to vulnerable people who have no fucking choice.
It's legal fucking robbery and they should be made to feel like the absolute shitstains that they are everywhere they go.
Like I say, welcome to the world of commodified prices.
Supporters of the system will tell you that it creates a level playing field for all participant countries, so that those without natural resources like gas can buy at a fairly the same price as everyone else.
Of course, not all countries sign up to this. Russia, for instance. Even prior to the Nord Stream 2 issues, they were at loggerheads with the EU over supply contracts. Previously, Russia had sold gas to countries on the basis of set contracts (that set the price and length of contract). Russia would sell at different rates to different countries, depending on whether they viewed that country as 'friendly' or wanted to arm-twist. They used gas supply as a soft-weapon. The EU insisted that all member states must buy at global market spot-rates. This benefited countries in western-Europe (who didn't have great links to Moscow) but penalised countries like Hungary and others with closer ties.
The UK joined the commodity party years ago. We had enough gas to supply us domestically for another several decades. But, under the Thatcher government, and especially post-privatisation, companies were encouraged to export gas as fast as they could pump it. Most of it went into the commodified global market. And even that which is used domestically is sold to UK market retailers at the global spot price.
The result of exporting so much gas is that we have lost energy security, and are susceptible to the sort of massive swings in energy prices we've just witnessed. But on the bright side, a lot of already rich people got a lot richer out of it, and the Tories were able massage down the enormous balance of trade deficit in the 80's & 90's.
Honestly, the older I get and the more is discover how things work behind the scenes, the more I realise we - the oiks - are being mugged-off on a vast scale. And only a bloody revolution, leading to every billionaire and city/bankster shitstain swinging from lampposts will solve it