The fast enough part is key. To generate a signal on the AM broadcast band you would have to rotate it at 800 thousands rotations per second. As for being able to interfere, radio signals are often in the microvolt/m range by the time they reach the reciver, and a strong magnet can produce a few volts in a small (10-20 turns) coil just being moved by hand. If you somehow managed to get a magnet spining at the 1575 million rotations per second as in the meme (without it disintegrating on contact with air, or getting ripped apart, or turning the air to plasma), it would produce massive amounts of field, tens of thousands of volts per meter.
GPS signals are actually especially weak, as low as 0.3 uV/m.
The fast enough part is key. To generate a signal on the AM broadcast band you would have to rotate it at 800 thousands rotations per second. As for being able to interfere, radio signals are often in the microvolt/m range by the time they reach the reciver, and a strong magnet can produce a few volts in a small (10-20 turns) coil just being moved by hand. If you somehow managed to get a magnet spining at the 1575 million rotations per second as in the meme (without it disintegrating on contact with air, or getting ripped apart, or turning the air to plasma), it would produce massive amounts of field, tens of thousands of volts per meter.
GPS signals are actually especially weak, as low as 0.3 uV/m.