This is a case of the tail wagging the dog. That is, the author writes as though the legitimacy of free speech in academia is dependent on whether Oxford Union debate can be shown to be legitimate. Rather, let free speech be deemed an axiomatic truth with the propriety of Oxford Union debate a simple corrollary issuing from that.
This is why the wider audience denounces social "science" as a fraud.
'Certain liberals accuse conservatives of fetishizing campus debate, arguing that debate has little to do with teaching and research. Yet if one adopts a wider definition of debate, this position breaks down. As scholars have long known, values have a critical influence during the research process; even quantitative research reflects philosophical positions. If political balances are skewed, orthodoxies will tilt towards particular ideologies.'