The reason for this is clear. Such debates typically lead to people attempting to twist the meanings of words in ways that are favourable to their views. The only answer is to outsource the business of defining these words to people who have training and experience in divining the precise meanings of words, and who do not have a dog in the particular philosophical fight.
Unfortunately, this is no longer true. See, for example, this recent tweet from Dictionary.com:
This is far from an isolated example of the social media teams of online dictionaries intervening in political discourse. See, for instance this article of 10 times Merriam Webster has majorly trolled Donald Trump. The common factor to these cases, of course, is that they are intervening from a progressive standpoint. It's not just the social media teams - the very fact that a dictionary is willing to include SJW terms like "mansplaining" is a sign that they are no longer impartial arbitrators of our shared language.Well, actually, mansplaining refers to the practice of a man explaining something to a woman in a condescending, overconfident, and often inaccurate or oversimplified manner. #ItsNotVeryNicehttps://t.co/0DXbJWmj6Q https://t.co/Jy1tTJWNEz— Dictionary.com (@Dictionarycom) May 29, 2018
The consequences of this are clear. We can no longer argue things "by definition" or "by looking up what the dictionary says", because these alleged "definitions" are being rigged. Moreover, any attempts to argue in this way should be taken as signs of braindead progressivism.