That's not a statement one way or the other about this particular editorial, but the WSJ editorial page does have a history of climate denial and I'd take their views on this trial with a grain of salt.
[1] https://en.wikipedia.org/wiki/The_Wall_Street_Journal#Editor...
If you're going to cite Wikipedia as authoritative, at least don't use weasel words at the same time - https://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Word...
There's a history of using the judicial system in this way in the US (particularly on race issues), partly because the judicial appointments tend to be the longest, and so judges can take the long view and make decisions that aren't politically expedient in the short-term.
In an era where the failures of the legislative branch to come up with good ways to deal with market externalities are culminating in mass extinction and global crisis, maybe it makes sense to try to get the judicial branch to find interpretations of existing laws that can help mitigate the problem?
In the current trial, the government is only looking to show that Exxon didn't plug in the right numbers to some financial models. If they can, they'll exact a huge fine to punish Exxon for causing climate change, even though they never proved in court that Exxon isn't allowed to cause climate change.
But you reap what you sow.