That’s true if it’s planted in soil but the plants adapt differently to grow in water and I’m sure you’ve seen cuttings root in water which is extremely common when propagating house plants. You can also find a lotttt of people who grow peace lily, pothos, monstera, barber palms, and plenty of other plants with no root rot. A peace lily seems to really thrive in an aquarium at long as you keep the roots out of the water and use fert. My peace lily roots are looking super healthy and it’s growing every day.
edit: oh I thought this was on the other post with the peace lily and red root floaters when typing that. Well now I’m much more sure of my chances being very low and now that I’m thinking about it, it could be toxic to fish even if it did work. I’m gonna have to look into it more