It's actually less risky. Most of the launches are of propellant, which is completely replaceable. Reliability of a launcher is achieved by using it many many times, exposing all the gotchas. SLS will launch so infrequently it will be extremely risky.

And you didn't answer my question, so I will answer it for you. If simply transferring a liquid from one tank to another is too risky, then there is no future in space. No activities of any significance could ever be done there. With that established, we can shut down the human space program and lose nothing of value.