I had a boss like this and I will tell you, it doesn’t get better. Even if you work faster/harder, they will always want more from you because you can never do it good enough. Multiple people left this job because of her (and even told her she was a micromanager!) and still, nothing changed. At one point, when I was the only employee left under her, she would spend her days in my online workflow (task management system) and just make comments. I didn’t know what else she did!
Similar to you, hours and hours were spent on her explaining things to me in meetings that I already knew. The kicker was that I taught her that stuff and I think she was explaining those things to me so she could actually wrap her head around these concepts.
Here’s the thing – you are a contract employee and you don’t have to keep them as a client. Work on getting new contracts and in the meantime, just push through. Sure, your boss may be a good guy (mine wasn’t a horrible person either) but as a manager, they aren’t working for you. I don’t think explaining this to him will make it better or help. You risk offending someone who basically has the authority to hire or fire and by going to them, you could inadvertently be putting a target on your back. When people went to my boss and told her she was bad, she made their job even harder passive-aggressively.
And no, I don’t think you’re being sensitive. There are a lot of bad managers out there but there is also a lot of good ones. Keep looking, and in the meantime, just do the best you can because and make mental notes on things you’ll never do if you become a manager. I’m sure you’ll have a big list in no-time!