To be less cynical, it's possible those venn diagrams don't overlap, or they've changed over time after removing layers of ignorance. There doesn't always need to be massive hypocrisy behind every motive, nor do we need to immediately shove our fingers that direction. Sometimes the world comes around to where people who thought this all along are now given a pulpet with which they will be finally heard.

So you don't want them to fight against climate change?

You have no clue what these specific people have done in their life, maybe they've always been activists.

Even if they were somehow involved in creating the problem then wouldn't it be a good thing for them to turn around and fight against it?

Why do you blame an entire generation of people? You think the average Joe is directly responsible for climate change?
You can blame leaders, politicians, etc who actually had the power to change things and the responsability to be aware of climate change and take action.
And if you say "yeah but they elected the politicians" I don't know what it's like in Sweden but in a lot of countries you have no meaningful choice. You have Trump vs Biden kind of options, always having to vote for the "lesser evil".

“Our tax dollars are benefiting younger generations. Quick! Somebody find a reason to sue the government, then have the cash buried with you!”