He doesn't change reality with his mind only. He does it with his mind and actions. That's still a form of reality warp. 1. He thinks of it. 2. He moves at a speed greater than most thoughts. 3. He has the reality warping speed force to do the rest. To someone on the outside he just warped reality with his mind because to them it looked like he stood still. By using a "he's not just thinking, he's thinking AND doing" as an argument while simultaneously attempting to shut other potentials down for doing the same smacks of hypocrisy. Or just a plain cheap "everything proof" shield. Hell why even worry about the just think guys because the flash has the speed force, moves faster than thought, and is wildly more creative than anyone. Scenario. ".God character" wills flash out of existence Speed force brings him back. Rinse repeat. Or Flash runs faster than God characters thoughts to reset the universe including said character.