The article tiptoes around the who and the why but it's pretty clear.

The US has HARM (anti radiation missiles) but it would be very easy for Ukraine, or anyone, to create an inexpensive drone, which you would program with a frequency, a signal strength, and a general direction and send it to ride the radio signal straight to the jammer. Repeat daily as needed.

Anything on the ground transmitting high power on GPS freqs is up to no good for the global community.