To start with, the concept of having water forcefully sprayed through one's butt seems fundamentally wrong. I don't know what is considered normal in France, but it certainly seems that in most places something engineered to do this would be frowned upon despite the fact that it saves paper. Now don't get me wrong, I'm all for the environment. I have energy efficient lightbulbs that take 10 minutes to warm up so that they actually light. I have an energy efficient showerhead that sprinkles down a fine mist instead of a decent spray. I don't sleep with the air conditioner on and, as a result, wake up in the middle of the night wishing other people hadn't trashed the planet that much so that I would have the opportunity to do so without guilt. However, I draw the line when it is no longer environmental to wipe one's own ass.
The real problem, however, is the stealth factor. The only time I have encountered something remotely similar to the bidet was when I found myself victim to a toilet-bowl squirter. It didn't actually bother me that much. The fundamental differences: it was a small squirt of water, and it was marketed as a prank meant, presumably, to annoy whoever found himself on the wrong end. The bidet is the exact opposite, ejecting a forceful stream of water into a perfectly unsuspecting toilet-user under the pretense of being useful. I don't want to get rid of them entirely; after all, those who enjoy such things have their right to them. I would just like to see a sign of warning somewhere. Perhaps a bright yellow sign that said in large red letters, "WARNING: This toilet will attempt to compromise your manhood" or something of the like.