Wikipedia as a whole is not 'progressive', it is whatever the editors make of it. Many politically contentious subjects have been - to use a word bandied around quite often in those circles - 'colonised' by 'progressive' editors who allow only their own viewpoint to remain in the articles which has turned those parts of Wikipedia 'progressive'.
If you're looking for the chemical composition of some substance or want to look up something related to physics or mathematics Wikipedia tends to do just fine. Articles on history are a mixed bag, especially recent history and especially anything related to 'the West'. For political subjects Wikipedia is less than useless given the aforementioned 'colonisation' but also because political operatives from 'all sides' do their best to paint as rosy a picture of 'their' side as possible.
If you're looking for the chemical composition of some substance or want to look up something related to physics or mathematics Wikipedia tends to do just fine. Articles on history are a mixed bag, especially recent history and especially anything related to 'the West'. For political subjects Wikipedia is less than useless given the aforementioned 'colonisation' but also because political operatives from 'all sides' do their best to paint as rosy a picture of 'their' side as possible.