That’s a hypothesis based on quite a number of unknowns; and quite possibly stretching a comparison beyond breaking point. There’s no telling what an alien civilisation would think like, including how they would treat other, less advanced civilisations. Of course it *could* spell disaster, I just think that it’s quite a long shot based on what’s known; and that it does not warrant the use of the emotionally-laden, in my opinion even slightly sensationalist “chilling”.
Assuming that the speed of light limit for space travel holds for them as well and the fact that this particular star is about 450 parsecs away, I don’t think it is very likely that their Columbus will touch down here anytime soon – even if we would be as visible to them as their star’s light curve apparently is to us.
I feel that a subject such as this, which is prone to have a significant impact on people’s worldview *if* it would ultimately be proved correct, deserves a rational and sober approach. In that sense I’m concerned that adding “chilling” is not just unwarranted, but likely to cloud some readers’ judgements as well.