Klass was a piece of work. It wasn't necessary, but he was often intellectually dishonest...and wasn't above the personal destruction of his "debate" opponents.
Klass was CIA or related Deep State—part of the disinformation and debunking operations.
He debunked UFOs for Project Blue Book Director Hector Quintanilla.
He traveled all over the world debunking UFOs with no transparent source of funding.
Most folks who have dug into this topic have concluded he was a part of Project Mockingbird.
That said—we still have no hard proof.
I think we will get it when all the Project Mockingbird files are declassified.
More of Klass—I have a copy of this book by him—it was a vicious hit piece full of logical fallacies:
https://www.amazon.com/UFO-Abductions-Philip-Klass/dp/0879755091