Not speaking as someone who has any experience in law enforcement, but just from the standpoint of reason along, the only time I can see using pepper spray on a suspect is out in the field if he's armed or otherwise dangerous (like on PCP for example) and you're trying to get him in custody. IN custody, I could only see it in a case again where the guy poses a danger, especially if he's significantly larger than the officer or officers dealing with him. For "punishment" or as an interrogation technique, no way. 62 year old man strapped to a chair, I don't think so. Even the "spit hood". Can't they just put him in a cell by himself or turn him towards the wall? "Spit all you want, ahole!"
If the officers in this incident had applied your thinking, we wouldn’t be discussing it because it wouldn’t have happened. :)
You’re right. Anything else means the cop lost his temper and in that case the other cops should step in to save the situation.