But one must still go to the sources Wikipedia uses and then use them as sources.
Not necessarily so. That depends on how deeply one wants to know about a topic and the time involved in order to do so. If one is not doing research but is curious about a particular topic, there is no necessity to do so. Consequently, one can rely on wikipedia as an accessible and valuable resource to inform and/or educate, without prejudice.
Many wiki articles are comprehensive essays which are carefully written by experts and as such, are useful and helpful overviews on any particular topic for one to obtain knowledge without the necessity to tediously search for sources (of which some are not free or they are highly technical complex papers), understand and evaluate them to determine their reliability wrt other sources and then and only then, to cite them.
OTOH, it is essential for one to learn and practice critical thinking rather than to look for, understand, evaluate and/or cite sources, with time constraints as the reality.
Critical thinking is a way of deciding whether a claim is true, partially true, or false. Critical thinking is a process that leads to skills that can be learned, mastered and used. Critical thinking is a tool by which one can come about reasoned conclusions based on a reasoned process. This process incorporates passion and creativity, but guides it with discipline, practicality and common sense. It can be traced in the West to ancient Greece with its Socratic method and in the East to ancient India with the Buddhist kalama sutta and abhidharma literature. Critical thinking is an important component of education, politics, business, and science.
Bold added by me.
Wikipedia itself is questionable
Generally, anything and everything, are questionable.
Wikipedia and wikis are resources, not sources. As such, and for the reasons stated in my last post, they are valuable resources and should be evaluated/used appropriately.