Hey, so I started a new save with the safety toggle for the flamethrower turned off. But once I got to the point where I could make one, and tried to burn down a forest with it, it was acting like that option was still turned on. Toggling it didn't fix the issue. What gives??

Also, why include that feature in the first place? It's not really connected to any other feature of the mod from my understanding, why not just have that be a separate mod instead of shoving it in here?

Created a new map. Turned off the fire safety of the hand flamethrowers. The forest caught fire.
Without your save, it is impossible to guess what exactly you did

Regarding "why hand flamethrowers don't set the forest on fire by default": the reason is that it causes very serious lag if the fire spreads or damages biters far from the player. In the 2nd case, all biters in a large radius check whether they can attack the base. Every tick of the game

If you think that the hand flamethrower without fire on the ground has become too weak, then I can say that to compensate for the lost damage from fire on the ground and trees, the direct damage has been significantly increased, so that the hand flamethrower is even stronger

As for stationary flamethrowers, they have not been changed. And if they don’t set fire to the forest, then the reason is not Rampant Fixed