Britannica isn't a viable source for most high school or collegiate work, either; should we ban it for students' own good? And what about textbooks? They offer an introduction to new ideas but are rarely appropriate sources for academic papers; indeed, their best use in such cases is as a jumping-off point.
I think that sums it all up right there. There is a lot of false or politicized information on Wikipedia but for a starting point when doing research it can usually help point you in the right direction. Especially since sources are usually not only cited but also linked.
If a teacher is complaining that students use it as a source just tell them not to and if they still do then just fail them for not following directions. Soon enough students will learn not to use Wikipedia as a primary source.
