It seems many people DO litter their own garden. Nature IS their garden but they only identify what is important to them according to limited self-interest and according to the way they have been conditioned (or brainwashed) by their personal experience, their 'tribe' and the information they follow. They have difficulty seeing the big picture if it doesn't affect them in personal ways. I realise this is a superficial answer to your questions.

I feel your despondence. It is important though, that you stay strong. You are right to question the lack of care of governments and many people but not everyone is at the same stage of understanding. We just got to continue doing what we can, however we can, to increase this understanding and particularly support the young.