I suppose I can see a bit of the point being made. Each swimming event is simply travelling a distance and making it harder or more difficult by varying the way it is done. Whilst a bit of a comical argument, it is the similar to asking someone to do the 100m backwards (backstroke) or by adopting a particular mannerism in your running technique. To match track events with pool events, you would only differentiate between distances and entrant would be free to use whatever stroke they felt propelled them to the finish line quicker so, potentially, some usng crawl, others butterfly etc.
There is sort of a point to be made that swimming increases its events by imposting technique rather than focusing on getting from A to B quickest.