Because there is still time.

We might not stop what is already happening or what will happen, but we still have time to make it less severe than it would be if no action would be made.

We still can save lives, not all of them but some and for this people it will make a difference.

Hopefully not average, but I guarantee there are forces out there actively pushing it. Two versions, eventually:

1. Don't do anything that might interfere with our profits, time is available/needed to consider what to do.

2. Don't do anything that might interfere with out profits, it's too late anyway.

In my family, about 5 out of 100 people believe climate change is even real. So ya, I think the average at this point is "I'm ambivalent, climate change may not even be real. But mostly I don't care"

I don't know anyone or ever see any media reflecting such a weird standpoint. It's more "better act now than even later"

The average view is that "climate change" == "higher/lower temperatures". Nobody really thinks of all the secondary effects.

a lot of people think that the time to do something is when your house is already flooded