You'd be surprised how recent those cedars might be, my friend. When we bought our farm in 1976, it was covered in little cedar seedlings, most less than a foot tall. The seller told us they had sprouted since the last year, and we should bushhog them so they didn't grow. Well, it took my stepfather a couple of years to get a tractor and bushhog, and those trees never got bushhogged. Those same trees were getting to be well over a foot in diameter the last time I saw them, which was probably ten years ago. It only took about 30 years for them to go from seedlings to as big as the ones you have there.
I know if you buy cedar, even rough cut. It's ridiculously expensive. But you sell your logs, mills don't want to pay you anything for your logs. Then they want you to deliver the logs.
I wish that were the situation on my place. The cedars suck up all the water from the ground and the other trees never get a chance to get any growth on. I'm planning on doing the same thing and getting them all culled out.
Yes get rid of em.... I'm a biology major and I hate mountain cedar trees. They are a burden to other trees and a burden to people. Where I live there was going to be a program to clear a lot of them out however there was concern about two bird species that make their home on them that are on somewhat of a decline. That project was scraped because of that.