I don't know why these people want to waste so much money and risk their lives to visit a planet which is already declared dead.
I think that for some people earth is just not enough
In more serious note, sometime in the future we will have to colonize other planets because we will destroy all the earth's resources.
From this viewpoint, it will be good idea to support this project now.
There's not going to be colonization of other planets, there's going to be more entertainment for people so they don't riot so much and at some point even technological development will stop
Then WW3, global hunger and burning hot temperatures
And only greedy people on this planet who only care about themselves
That's the future