You guys do realize that the original post was not about actually INSERTING the IV line on Yom Kippur, right? And there may be non Jews working on YK to hook up the IV fluids.
These are done I assume for patients, pregnant women or the elderly that know in advance that they will have significant hardship and perhaps endanger themselves by fasting yet would rather not drink — even though some may give them a heter to do so. It’s planned so actual chillul Y”T is avoided and Hatzolah members are saved from running (driving) to so many emergencies.