If you go back to 4th edition, there are several humanoid drones you can convert over. As for why there aren't many humanoid drones around, Deus's drones aren't really the issue. It falls down to the difference between Versatility and Specialization. The humanoid form is a very versatile 'platform'. You can traverse lots of different environments better than tracked or wheeled drones, and can maneuver cramped spaces better than flying drones. You can carry arms and armor, perform maintenance, and do any number of other tasks. As such, if you want a 'generalist' drone, you could do a lot worse than a humanoid form.
On the other hand, specialized drones benefit from being able to focus on their role. Combat drones are optimized to carry weapons. Wheeled or flying drones can be much faster than walkers. Surveillance drones can get to areas where a walker might not be able to, either due to size or movement modes. And, more importantly, specialized drones means people have to buy more drones, rather than having a 'catchall'.
That said, there are some examples of humanoid drones in SR. Other than 'helper' drones like the Manservant, the majority of them fall into the realm of dedicated cyborg bodies, which means they're hard to get and ungodly expensive. Otherwise, there is the Ares Duelist (a dedicated blade-wielding drone) and the TAN-DEM from SR4's MilSpec Tech 2 book, which is basically a security drone with a gun for one of its hands, and isn't very useful outside of that role. By far, the most useful humanoid drone I've seen is the Nadeshiko from SR4's Rigger 4 book. Yes, it was a 'joke' product, but the Nadeshiko is still a great drone for anyone who wants to have a few drones that look like metahumans.
But there's only a few reasons for someone to have a humanoid drone that actually looks like a person:
1) They are trying to hide the fact that they're using a drone. This could be an AI or cyborg's main body, and they want to fit in with everyone else, or someone who uses their 'Doombot' to keep the <s>Fantastic Four</s>runners from capturing them when their plans are foiled.
2) Loyal security that doesn't look like "Oh, drek, he brought a half dozen combat drones with him!"
3) Pervy reasons.
4) Some combination of the above.