Fringe positions can be revolutionary and important. More often, they are reactionary and not well thought out. There is nothing wrong with advocating for a fringe position. But you better have the intellectual goods, and not just win arguments by default by suppressing dissent.
The latter is activism. Controversy should mean giving opposing view points a fair shake and judging between them by the strength of the data and arguments supporting them. Not by university administrations unilaterally deciding and declaring dissent as "unsafe" for the students who don't want to be exposed to anything that challenges their world views.