Futurology

There is no guarantee that we’ll have immunity to such things. There’s no guarantee that they won’t eat up everything in the ecosystem.

Given that all the sugars that currently exist in the ecosystem would be the wrong enantiomer for them to eat, I think we can be reasonably confident that they won't eat up everything.

Both forms of life (or proto-life) must have existed in the early days of the Earth, and eventually one chirality won out. If we create 'mirror life' today, it would be the same as existing life, just severely maladapted to its environment.