The comment didn't say "transportation is carbon neutral", they said it can be. You point out that the world depends "mostly" on fossil fuels, which correctly implies that there are instances in the world where this isn't the case.

e.g. Transportation using EVs that get all of their charging from a solar installation.

Respectfully, you're wrong. How are the solar panels built? How is the material extracted, modified, transported? How was the road you use built? How was your EV built?

You can't just say "look, I am carbon neutral because I consider that the carbon that was extracted to make my electricity counts for somebody else", that's just naive. Either you live in a carbon neutral world, or you don't.

Fact is, we are not even remotely close to living in a carbon neutral world, and renewable energy does not remotely promise to replace fossil fuels. Hence the more energy you use, the bigger your carbon footprint. We need to use less energy, that's all. There is no green energy.

There are two things that really need to be accepted:

First, we are living a mass extinction, and that's not because of climate change. Species disappear essentially because of habitat loss, pollution, pesticides, deforestation, etc. The mass extinction is due to how we live with all that cheap energy we have. Finding an infinite clean energy would not change that. Hence we need to use less energy.

Second, fossil fuels are screwing up the climate, which will add to the biodiversity problem we already have. But this is just getting started. The thing is that we don't have a solution to replace fossil fuels at scale. And if we did, that would still leave us in a mass extinction. Hence we need to use less energy.

Technology is not the solution, it's mostly the problem. We need to do less with less. Urgently.