It is actually a fairly contentious issue. Band of Brothers isn't generally criticized for it's portrayal of Sobel but at the same time while it does make him look a bit incompetent as a commander, at the same time he has been credited by a number of officers in Easy Company for the company's future success, including Dick Winters.

As it were, he made for a good drill sergeant but an awful captain.

I looked up Sobel recently, and found this long article about him http://everything2.com/title/Captain+Herbert+Sobel

I hadn't realised he was Jewish. I wonder if some of the antipathy directed at him was based on his background and appearance.

Whatever the ultimate cause he was certainly deeply disliked. During one training exercise the medics put him under general anaesthetic and cut an appendectomy scar into his abdomen as a prank! I can't imagine this happening to an officer who inspired a shred of respect.