No. Anarchy is undemocratic, because for practical purposes, in an anarchic state, the strong rule the weak.
This is a radical over-simplification to the point of being nonsensical. There are dozens of flavors of anarchy, all of which have their own unique relationship to this statement. Of course, one could suggest that anarchies seek to weaken the rule of law, and thus afford the strong greater ease in subjecting the weak, and in some cases that's a reasonable claim, but that's not what you said.
In the modern world, an open source project is utterly democratic, because everyone gets one voice, and no one can suppress it.
If that were sufficient definition of democracy, then prisons would be democratic. Everyone can yell into the central halls and all anyone can do to suppress your voice is to commit violence against you (e.g. shut you up physically), which is always an option in any situation where members of the social group have access to one another.
No, the definition of democracy hinges on a social contract whereby the society as a whole agree to be bound by majority decisions. The ability to partake in that process is only the first step. Open source projects rarely require such a social contract (some of the larger ones do). They are typically loose confederations which behave as benevolent dictatorships and whose resources the group is allowed to leave with, should they decide to disband.
The reason this is practical in the open source world is that the resources have no inherent cost other than time, and their value is not diminished by forking. This, of course, is not true of land, food and natural resources, which is why the open source model doesn't work in the real world.