They went to the playoffs with him twice, so it wasn't like they didn't win anything with him.
And for most of Sammy's career, he was nearly the only reason to get excited about the Cubs. Certainly the number one reason to consistently tune and watch the games from like 1996-2002.
I'll sometimes play random games on YouTube while I am working, and I am always amazed at just how awful the lineup around him was for much of his career. Just brutally bad outside of he and Grace, and I guess I was so enured to the Cubs being bad back then that I didn't appreciate how awful some of those teams were at the time.
Though shut out of the playoffs, at least mid-late 1960s fans had Banks, Williams, Santo and Jenkins to watch. Four hall of famers.
I became really invested as a fan (as opposed to just being the kid of a Cubs fan) in 1987 or 88, and outside of the decennial playoff appearance (which felt more like an aberrant gift than anything), the primary reasons I ever had to feel excited to watch Cubs baseball on a daily basis was Ryne Sandberg for a handful of years and Sammy Sosa. And though Ryno was my favorite as young kid, Sammy was the most exciting player I've personally seen in a Cubs uniform. It was must see TV and I loved it.
Obviously the steroid thing diminishes those memories a bit, but it doesn't nullify them, or even close to it.
And the notion that he be ostracized by the organization until he repentantly abases himself to a repellent chode like Tom Ricketts (who wasn't even associated with the team until long after Sammy was gone) is absurd.