VPNs could turn purely domestic communications into “foreign” communications the NSA can legally intercept

Lol. Then they go and immediately say:

and the FBI, somewhat less-legally can dip into at will

In other words, they don’t gaf about your sovereignty, and will monitor communications in any way they want, legally or otherwise.

They’ve been illegally digging into domestic communications for decades. Stallman and Snowden (to name a couple) exposed that a long time ago. Hell, the USA government exposes themselves all the time, the USA people just choose to ignore it.