The flavour of toothpaste (assuming mint) isn't what makes it gross, it's the texture. The taste makes it palatable in your mouth (or at least that is the intention). When I was a kid, cinnamon toothpaste was an option as well. IIRC there are plain options, but they're worse. I've made mint frosting (since shops don't seem to sell it, Wilton's buttercream icing but with peppermint extract instead of vanilla) and my wife says it tastes like toothpaste. Her sister, my niece, and I all love it though. My wife's the odd one here. Mint aversion isn't really that odd, though. It's just a flavour and not everyone is going to like it.