Very valid. As per this thread - The Colbert Full-Body Workout Plan! - Robstein did the program and said sessions “always took at least 90 minutes”.
So yeah, if one hour is a necessity due to your schedule, then that’s a non-starter and picking a different (pre-written, expert-designed) program is the right choice. If the one-hour thing was supposed to maximize hormones or recovery or whatever, then understand that that’s basically a debunked non-issue as long as you’re eating properly, sleeping well, and actually following a decent training plan.