Why should she moderate her language exactly?

To make you more comfortable? Climate change and its impacts have been known and understood for more than twenty years. Al Gore did a documentary in what? 2003? Her message is hers. What people do with it is up to them.

This sort of concern-trolling is how and why nothing has been done. Ultimately it is a political issue, as individual actions, no matter how praiseworthy, are not going to be enough.

How dare you, indeed.