OT: The alien threat is a bad example. We would be 100% at the mercy of any intelligence that makes it's way to us. They could destroy us with the blink of an eye before we even realized because their technology would be so far superior. Think of a modern army against Roman empire. The only thing we could hope for was that they/it would also have high moral standards. Maybe it's not so smart to send radio waves into all directions...
Haha, it's perhaps entertaining to link thoughts of war against the aliens to aliens, but as you stated there between the lines, there's likelihood/hope they would actually be smarter than just a warmongering space barbarian... Which the common image actually seems to be most of the time at this moment.
The alien is a psychological archetypal character that can be used as an object to narrate beliefs of the emperor to the common folk trough means of mass production and it's greatest field of societal programming apart from the education field; the entertainment industry. A giant engine of PR aka. propaganda for the almost monarchistic state. Power, again... yet again... grown behind closed doors, away from the public, off from the streets.
Being afraid of the alien and projecting it as a military threat is a powerful way to link the thought that the unknown solutions, technologies, thoughts, creativity... is only in the realm of the war machine. Be afraid, be very afraid.
But if the concept of aliens is taken seriously and not used as a ridiculous puppet, as a genuine reflective tool to think about human possibilities...
Don't you think that ANY highly sophisticated society of alien intelligence would actually be very peaceful and wise instead of fearful and tribal.
If you take a neurologic viewpoint, this would be a wrong evolutive direction to follow the observations...
Intelligence is about understanding. Real intelligence is not harmful. Real science is always about good ethics.
It comes from rational approach to apply rationally confirmed knowledge into a process of understanding.
It would be safe to assume that any self-aware planetary race would have to solve the questions and challenges of the questions about spreading wealth and population management as a whole. It is the biggest challenge of humanity right now and basically everything that we ever discuss in the fields of the sciences, politics, social studies and economics. That's what all the fuss is about, that's why there is something we call "News". We look at the developments of this lunatic social experiment because we are just too damn lazy to catch and cultivate our own food.
Well, that's the first intelligent being process all about... Reaching adulthood, balance of body and mind and self sustenance without tantrums and violence.
That's what the aliens needed to figure out FIRST, before they could develop tech further, otherwise been lost into space due some stupid disputes. That's precisely why the big nations do space programs together.... The scientists are trying to keep up having world peace challenging the best of these nations work together on a bigger quest. To keep the frustrated men off each others throats as this political madhouse tries to settle itself.
Aliens, obviously would have had to been gone through all of that and way beyond.
And using alien to connect unknown elements into ridicule or fearful scenarios is mental image manipulation to hold psychological leverage against progressive thought.
So no, I don't think sending radio waves to space is all that dangerous
The dangers only exist likely on the silver screen. Real aliens would be magnificent beings in greater likelihood if you take a broad look on nature and the universe.