I need some clarification, preferably a reputable source, that the attacker gets to choose which square they push their target into, as long as that square moves the target further away from the attacker.
That's about as good as you're gonna get...PHB 57 said:If a hit grants you the ability to compel the target
to move, whether through forced movement or teleportation,
you can move it any number of squares up
to the number specified (or not move it at all, if you so
choose).
I agree with the adjudication, it's just that a DM has adjudicated otherwise, and the Push description does not explicitly state that you choose where the target goes, only that the target must move away from you.
So again, I ask how the alternative interacts with Slide?
If I Slide a target three squares, does he feel that this means the target can move three squares in any direction, and I have no influence over where he goes?
-Hyp.
I'm looking really hard but struggling to find where it was exactly I asked about or mentioned or even inferred anything relating to or even could be construed as asking about, slide.
Nope. Nothing. Maybe you'd like to fork the thread into another discussion about slide and how it relates to push?
Kzach, he's offering you an argument that could be used to show that your DM's interpretation is silly. Figure out where the point is going, then go to your DM about it. There's a chance it'll change his mind.