Ethics or Rules Question

[Bill in FL]

I was playing a $5.50/18 player NLHE sng at pokerstars. There were 6 players left, I had folded my hand. The short stack went all-in, both big stacks called. Big stack A wanted to check the pot down, big stack B wanted to fight for the pot. Player A ended up folding and the all-in was eliminated. After the hand an upset player A typed in the chat box "DO NOT BET WHEN WE ARE ELIMINATING PEOPLE". I know this is good strategy but is it legal and/or ethical to talk about it during the game?

Thanks
Bill