Prior to the revelation around the aliens receiving his logs, Eiffel's logical expectation is that the only people who'll listen to his logs are people at Goddard Command. And yet the way he speaks in those logs is often not really addressed at Goddard staff. For example, in Ep8 The Empty Man Cometh, he says:
Oh, hell, speaking of logs... I guess you caught all of that, so you might be able to pick up the effect your twisted experiment had on us. Hint: IT WAS AWFUL.
Sorry if things got a bit crazy for a while there, dear listeners, but... well, you see the kind of things we have to deal with.
The first part of that quote is obviously directed at Goddard staff, at the people who create many of the situations Eiffel and the rest of the Hephaestus crew have to deal with (such as the empty man panic). But the second part - the part addressed to Eiffel's "dear listeners" - feels like a switch, like it's directed at a sympathetic audience who are witnessing Eiffel's plight without having any role in it. In other words, it feels like it's directed at us. Before the aliens come into the picture, we are the "dear listeners".
There's no logical reason for Eiffel to make this kind of switch between the listener he blames (i.e. Goddard Command) and his more sympathetic "dear listener". He's mentally constructing a listener to his logs who is on his side, when he has no in-universe reason to believe that there is one. It's an interesting kind of coping mechanism - potentially linked to the unconscious, perhaps misdirected, desire for connection that led him to transmit his logs into deep space.
There are other signs that the "dear listener" Eiffel directs his logs towards has very little to do with Goddard, such as the way he explains things that Goddard staff would obviously know (which is obviously useful from a storytelling perspective, but also feels in-character and in line with his other behaviour), as well as telling the listener things that could land him in trouble with Goddard.
Eiffel is the kind of genre-savvy character who is regularly on the brink of fully breaking the fourth wall. He doesn't know he's in an audio drama, but he's so prone to narrating his life that he might as well know. He's always constructing the narrative of his life in his head, so perhaps he finds that it helps to imagine someone on Earth who is listening sympathetically to the story he's telling himself. In his world, at the beginning of the show, he doesn't have that listener, or doesn't believe he has. But his words reach across from the universe of his story into ours. And his voice finds the kind of dear listener he was imagining without hoping for - someone who has no role in anything that happens on the Hephaestus but who is willing to listen to his story. In pressing play on your podcast app, you become the listener he was longing for.