We should care about Microsoft's licenses exactly as much as Microsoft cares about ours.

Only if you have a lawyer department as large as theirs.

But to be fair/realistic, as an individual, I've never worried about their licenses (for myself, my friends, and family). The only time I did was when installing their software in professional/commercial contexts, that's where they do most of their enforcement as far as I know... and only when the scale is egregious.