@JPfeiffs in the tiger argument we are told that tigers are aggressive, which is what makes them unsuitable to be pets. No external knowledge needed. Unless of course you are trying to consider that some people may be ok with aggressive pets? While that could be considered it is outside the realm of what would be considered average, as in most people (based on my general knowledge) don't want aggresive pets. Do you think that that claim "most people don't want agressive pets" needed to be stated in order to make the argument valid? That's an overthinking trap that I have gotten into as well