I likewise have talked to many good researchers who hated to teach. And when I have sat in their classes I have found that their students quite rightly disliked being taught by them as much as they disliked teaching.

Teaching well and doing quality research are different skills. Setting good researchers in front of classes does not result in good teaching. Making researchers teach classes without quality feedback while rewarding them almost entirely for their research results in dreadful teaching.

One of my favorite books is about exactly this. It focusses on math education, and explains why the state of math education at the college level is so dreadful. (The problems there tend to trickle down, but that is another story.) And it isn't just a rant, it is accurate, and the more you know the more you can recognize that accuracy. I have seen mathematicians say, in all seriousness, "That book is my biography."

And, as I just found out from Google, this book is available online! Why the Professor Can't Teach by Morris Kline. The next time you see someone suggesting that ability at research is a good qualification for teaching, I suggest handing them this link.

(An incidental note. The author, Morris Kline, was both respected as a researcher and an educator.)