It casts doubt on our previous ideas on how necessary it is for galaxy formation. I would actually argue that this strengthens the case for dark matter. For example, the link in the OP discusses galaxy rotation speed which typically mismatches what we would expect based on how much visible matter we measure. If there was some other explanation for that discrepancy, e.g. overestimating galaxy mass or modified theories of gravity as your link argues, they would have universal effects. The anomalies present in this result show that whatever is causing the typical unexpected galaxy rotation speeds is unlikely to be such things, bolstering the case for dark matter.