Well now he did electrocute
Topsy the Elephant but that was because she was a rogue elephant and had killed three people. Apparently not entirely or even really her fault as her trainer had been abusive. But the point is, she had killed three people, so for that reason, her owners were determined to kill her, and if
Edison hadn't done it with electricity, they would have had her killed some other way.
As for other animals, well I guess if you're sentimental about animals, although I am not.
As for electricity as an appropriate method to execute humans, well not only
Edison but the majority of US States thought it was more humane than hanging and they thought that for a long time, long after
Edison was gone. Prolly really wasn't, but the intent was good.
As for executing one of his employees who volunteered to be a guinea pig, do you have a source for that? I've Googled in vain to find something about it.
I kind of think he was hot when he was young.
Now, me I hate
Robert E.
Lee. But
Lee is too common a name to be associated only with him.