I always love that logic ... our planet is too dangerous and dying, so we have to leave to make sure we survive

At this point in our evolution ... we would ensure our long term survival in our galaxy if we stayed put and maintained our current environment. It's the only liveable atmosphere, environment and planet that we know of that we can live on and have access to.

How are we going to restart life on Mars where there is no atmosphere or resources when we're doing such a terrible job maintaining the existing atmosphere and environment we were born into?

I always like burning house metaphors .... space exploration to save our species at this point in time is like burning your house down, telling everyone you can't live there any more and saying that you're leaving to go live somewhere else where you can decorate a better bedroom. Except your burning house is located in an isolated desert with no shelter for hundreds of miles around.