:::I used activist to describe political activity directed towards Flemish nationalism.  If you choose to see activist as a POV word, I cannot help you.  Some people, who are not necessarily Flemish, see all separatist movements as inhumane. For them, Flemist activist probably implies a negative connotation. Do you deny that Dewinter founded, or help found, the Vlaamse Studenten Actie Groep?    
 ::::I don't know whether he did. It is not relevant, I think. Do you have sources that call Dewinter a Flemish Activist, or is it just your opinion ? In the latter case, putting that cat there is original research.  
 ::::Or are you going to put everybody in this category that has had "political activity directed towards Flemish nationalism" ? In that case, you should at least add someone like Wilfried Martens...