The article assumes you need faster than light travel to make aliens potentially dangerous. You don't need FTL. Relativistic travel is dangerous enough. The time of danger will approach when we start to develop relativistic spacecraft. If we can do that, then we could also develop weapons using that technology. Once we reach that point, we become dangerous enough that aliens might be interested in wiping us out.

The problem with relativistic weapons, is that there can be no Mutual Assured Destruction if societies that resemble the current human civilization are involved. High relativistic velocities can preclude detection with significant warning time. If the first strike can be coordinated to completely wipe out the enemy, then there is no chance to launch a retaliatory strike.

If intelligent aliens already uploaded their minds into their starships, then it would be safe to deal with them. A civilization composed of such sentient starships would be impossible to wipe out in a preemptive strike, so there would be nothing we could do to them, and there would be no reason for them to fear us.