It’s not “what if we decide he’s super cool later” but instead “what if we decide later the new name is also bad, so we end up repeatedly changing something that we’ve deemed shouldn’t be changing”.
Somethings in the scientific community should not change — I.e. what we consider as 1 gram should always stay the same so experiments can be reproduced consistently. I’m not sure I agree with them that names should be one of them… but I’m not a scientist studying plants, so the heck do I know?