The Furminator is a blade, and yes it does damage coat when not used properly or used too often or for too long. Most people who overuse won't notice because they are not showing their dogs, or the dog has a bitch stripe or "salt and pepper" already so it's not as noticeable if you don't care about coat texture.
I will never use one and don't need to. I mainly use a cheap rake, but have a pin brush as well. I show my dogs so I am a bit more particular about grooming but as long as the dog's coat is healthy and well maintained, I've never needed a tool like a Furminator to start cutting out coat. I do have a cat Furminator that I've used once or twice to remove small forming mats behind my mutt's floppy ears. In this case it was coat that needed to be "cut" out.
I will never use one and don't need to. I mainly use a cheap rake, but have a pin brush as well. I show my dogs so I am a bit more particular about grooming but as long as the dog's coat is healthy and well maintained, I've never needed a tool like a Furminator to start cutting out coat. I do have a cat Furminator that I've used once or twice to remove small forming mats behind my mutt's floppy ears. In this case it was coat that needed to be "cut" out.