I don't know how bad it is at the high school level, but it does get worse as you go up to the University level...

For an example, take the 2014 CEDA Championship Debate held at Indiana University -

https://www.youtube.com/watch?v=fmO-ziHU_D8

* It seems that all the original videos from the above have been removed (from youtube), only clips are available.

For those that are interested, a response to the criticism of the above "debate" was made that is itself cringe-worthy and difficult to watch - https://www.youtube.com/watch?v=0Pij5Sg4_DY