Never came across a heat pipe denier, this is new.
No, that's not how that works, you can have a vacuum chamber with liquid inside. You're probably imagining that if you suck the air out it will suck the water out as well but the physics don't work out that way. Zero pressure (or close to) is insufficient to move a fluid, you need more than that, obviously. The water will turn into a gas as you are lowering the pressure, obviously they stop before that happens, it would defeat the purpose.
But according to your logic there shouldn't be anything in the heat pipe, because whatever you put in there will be removed when it's vacuumed right ? So what's in there ? Nothing ? Why do they call a heat pipe then, it would just be an empty copper tube.
How do you think this works ?
I already explained to you the inside of a heat pipe is porous, it's like putting a drop of water on a sponge, you would never be able to tell that there is some water in there unless you squeeze it. You can't really squeeze coper can you ? If you open a heat pipe in an enclosed chamber and increase the temperature eventually the little water that is in there will condense on it's walls.