cards speak or players?

[ACPlayer]

Lat night at the Borg.

Player 1 and Player 2 are in a grudge match trying to outplay the other.

Bunch of fish fold, Player 1 raises, Player 2 3 bets and all fold. Flop, turn, river plenty of action. The river board looks like K J J T 9 something like that. Player 2 shows first 8-5 suited. Player 1 looks and looks, no one says anything. Player 1 starts to throw away the hand face down towards the dealer releases the hand but dealer is slow, no one says anything. Player 2 now says something like -- throw it away I got a straight. Someone now says -- "that's not a straight". Player 1 pulls back the hand and shows pocket 7s.

Appropriate/Inappropriate for a player to say that?
Appropriate/Inappropriate for the dealer to say that?

Incidentally, Player 1 could have been deliberately slow rolling and Player 2 could have been angle shooting or actually thought he had the straight. This was a grudge match and the players were not tooooo bad, definitely not newbies.