My son, who loooooooves power point, asked me why.
My problem is unique to me. Power point forces me to tell my story in what is, for me, an entirely unnatural way.
Understand, I never plan my speeches in advance. I make a set of bullet points to acct as notes to myself. It is the same method I use to prep stories for telling. My talks are like stories. They flow. I shuffle the bullet points or drop or discard them as I please. Sometimes I add things. It is all very spontaneous.
Power point requires me to do stuff in advance. that's already bad. I never prepare in advance, with the exception of researching key facts or quotes. Worse, the ppt requires me to set the basic text and order of the speech. It is impossible to vary the order spontaneously. It is impossible to drop slides in a non-obvious way.
It is altogether miserable and loathsome. It is torture. It is like trying to feel relaxed in a straight jacket. The fact that the rest of the world thinks this is the "natural" -- or worse, prefered -- way to prepare for a public speaking engagement only adds to the loathsomeness.