Because it serves no function other than to clutter the screen with text and say "yay, well done you, you did a warp-strike, an ability that takes no effort to pull off at all*clap clap clap*!
It's obnoxious and has no purpose being there.
And I've no need for button prompts that add to the mess on the screen. Be a bit more subtle like in ED(ED would have been perfect if it was just the enemy flashing and didn't show the button to parry).
Have they gotten rid of that stupid red shield and red ring that comes up when you are prompted to defend? Doesn't matter if they haven't as long as you can turn of the prompt al together.