I had a similar experience, renting a small shop space to store my cars/bikes and have a place to work on them. The lease was set up for a business, and had liability insurance provisions. I read through and highlighted the parts I had questions on, and the agent (who was very helpful and easy to work with) struck all of them, no questions asked. He said it was just a standard business lease, so a lot of the things in there wouldn't apply for my situation, but they only have the 1 standard form. Pretty much everyone else in my industrial park was a business.
Also, just to give you a data point, the requirement on mine was $1 million liability insurance, I called around and got a couple quotes, most came in around $500/year, so even if you do have to get it, it isn't TOO bad. In my case it ended up not being required.
Cheers.