You're fermenting grain with pretty much the same yeast that is used to make beer. It's probably not surprising that it smells like it. What you're making is much closer to beer than a starter.
As pointed out in the other thread, you're not making a starter (as in sourdough starter) when you add commercial yeast. A starter, as the term is used in this forum and most others, is a symbiotic culture of yeast (not the same species as baker's yeast) and lactic acid bacteria (LAB). When making a starter, you're making an environment that is favorable for these wild yeast and LAB can establish themselves and take over so that other wild yeast and bacteria can't. Once they are established, regular feeding keeps them healthy enough that generally other yeast and bacteria that come along can't take over, and even if they do, it's not necessarily a bad thing.
"Bad" is kind of a nebulous term as applied to cultures. Yes, a culture can go bad. That may mean it gets contaminated with a bacteria that takes over and makes it smell like a backed up sewer. Band can also mean everything smells great but the particular culture is no enzymatically active that it will literally turn your dough into slop.
