Why I avoid using trendline

This is one of some analysis that I was shared to my students on the group.
Based my experienced, I NEVER BELIEVE analysis using trend line ( diagonal line ) will give me high accuracy !!!

And this is the evidence, AUDNZD after price breakout the top diagonal orange line, the trendline trader , I am pretty sure most of them thinking price will continue up and open buy position. But it just trap! False breakout !!!

Me and my students together we opened SELL position, and let profit running until touch last yellow horizontal line