Please in the future learn to respwn to an entire post, don't nit pick, it's super annoying to respond to nitpicking.
I don't think pacifist is the right word. Pacifist means, they would not respond even when attacked.
Also war declaration only works, if you can communicate with them. But you can't. So blah.
The last 3 paragraphs you took out of context, so your respond makes very little sense.
But what i will respond with the same reply i did few month back when same argument came up: Show me the picture of an Thargoid pilot from the game Lore!
And don't try to tell me that for 5 years of war, no one saw a single Thargoid pilot? That's impossible.
So yeah, they are machines.
I replied to your entire post, going through it point by point because I thought that'd be clearer. I'll do it this way if you prefer, but you will see that what I quoted was just your post, in order.
Yes, I don't think they're pacifist. I brought up pacifism because that would be the only scenario where the Thargoids would not meet your criteria for being hostile. Obviously that is not the case, but there's still a big gap between that and outright hostility.
As for the picture of a Thargoid pilot: can you blow up a human ship and show me a picture of the dead pilot? The base game is PEGI 7, I don't believe you can have corpses lying around. Blow up a human ship, and the human you can see in the cockpit will just vanish. You'll have to wait for Odyssey exclusive Thargoid encounters for that, assuming Frontier want to ruin the mystery of what Thargoids look like.
Regardless, we know from the lore that the ships are piloted, that the Thargoids are, well, alive. Check the codex, or the INRA logs that detail how
they experimented on live Thargoids.