>>34302904>>34302912>>34302918You get burnt when whatever is hot enough to burn you lingers on your skin, it's much easier to burn oneself with boiling water than it is with open flame. The distinction with most Fire moves is that the flames don't linger, something that is implied with Scald. The difference between Flamethrower in Pokemon and a real-life flamethrower is that Fire Pokemon don't seem to need a fuel source, they just emit flames. A real-life flamethrower shoots a stream of fuel that it then sets on fire, which means you aren't just getting hit with flames, you're getting covered in burning fuel which continues to burn you. Unless something is crazy flammable like dry grass just having flames near it won't be enough to set it on fire.
I do think all Fire moves should have an inherent chance to burn the target based on what type they are, but that's a different discussion.