Agreed; I have strong opinions on the (problems with) fermi paradox solutions, but it’s taking us into very familiar territory.
Perhaps if @HeyHomie can specify whether he wants contact being a possibility or not and we can park the discussion of distances?
I’m not sure what you mean here. Is contact with an alien civilization possible? Sure. We could get a clear and unambiguous message from them before the day is out today. Or it could be ten years from now. Or it could be 50 million years after another asteroid wipes us out (and it would fall on the deaf ears of the New Dinosaurs, one supposes).
I’m not @mijin but I thimnk they meant contact in the movie Contact sense of the word. IOW, Aliens show up on Earth in person or we go visit them in person. The two civs are not merely communicating back and forth via messages of some sort.
Oh, no. Face-to-face (as it were) contact is off the table. The physics would make it impossible, no matter how advanced the alien civilization.
Well how impossible is an open question but anyway, it’s clear for this thread: just messages in a bottle, no contact 
Assuming they have radio telescope arrays sensitive enough to pick up our transmissions out of all the background noise, how much could they actually watch? The vast majority of our transmissions are now digital rather than analog, rendering them effectively encrypted even when not actively encrypted.
“We know Earth is flat and you’re just a hologram. Buzz off.”
That’s a point we’ve gone around a few times too. The window of time where humanity had mastered radio and before we mastered digital radio with very fancy waveforms and encoding was barely 100 years.
The former stands out from natural signals and is readily received, processed, and the content retrievable to anyone. with that level of tech or higher. It’s dirt simple and you don’t need the engineering specs to figure it out. The latter is almost indistinguishable from noise at any tech level we can imagine.
Your valid point here is noted, but it’s mostly applicable to classical noise, where you may be able to integrate over long periods of time. That’s usually the only kind of noise we’re concerned with in classical poor S/N situations.
But it doesn’t really apply to quantum noise, which eventually and inevitably comes into play.
First, when you’re receiving only one or two photons at a time, you’re now dealing with shot noise – manifested as random photon arrivals, and you cannot get rid of the randomness. Second, there’s a theoretical quantum limit on amplifiers, derived from the Heisenberg uncertainty principle that says you cannot amplify a signal without adding quantum noise.
In the real world, with some finite data rate requiring reliable decoding with realistic receivers, these factors become dominant just becuase you can no longer extract arbitrary information from arbitrarily few photons.
"OK, but we have monitored your primitive comms systems for several of your earth generations and you have quite nasty hegemonic tendencies and a predilection of asserting violence prejudice to any species you come into contact, even your own. Please stay in your little sand box. And anyhow, you are made out of meat. Who wants to talk to sentient meat?
Whatever we do, don’t tell them how beautiful our women are.
After all …
I’m thinking that within a few centuries of radio invention curious beings on both sides would target plausible planets with highly directional antennas. They would deliberately avoid strong encryption.
Maybe a few advanced civilizations do not have curious governments or rich beings who would want to do this. Seems unlikely to me, but those will be missed.
If they send us a book titled “To Serve Man”—they are giants, with great big Badminton Rackets.
The rest gets messy.
“We come in peace! Shoot to kill. Shoot to kill, men.”
Few places more peaceful than a cemetery - Humanity.
I see what you did there.
No, it works for quantum noise, too. Yes, getting only a handful of photons is a problem, but you solve that problem by getting more photons. A bigger receiver and a longer integration time will both let you do that. At some point it gets impractical, of course, but what constitutes “practical” is inherently difficult to pin down.
They’re coming to get you, Barbara.
I’d send them a game of tik tak toe.
Can they discern the game? If we send them an example, and then a blank board, surely they’d figure it out.
Of course, the most likely outcome - if we got a game going - would be a draw. The movie Wargames once taught us that “the only way to win is not to play” - is there some philosophical message that we’re conveying?
I’d be interested in their response. I wonder if they’d send us one of their simple games. An entire planet would be working on figuring out how to play.