Because there is no company that they could give it too that has both experience and a better track record. Its like saying why are you using linux, don't you

Because there is no company that they could give it too that has both experience and a better track record. Its like saying why are you using linux, don't you know it has a knowing history of having bugs. Sure, but show me the alternative that never had bugs. This tug not working correctly could mean dropping the ISS on a major city. So they are not gone trust some new unproven company. And there are simply not many companies that can do that stuff. Being late on a highly complex experimental project is totally different and a different part of the company. This tug is much more likely to be derived from their existing Dragon contracts and those have an amazing track record of execution in the last decade.