For the same reason most people who oppose this do: it will create multiple names for plants and sow confusion. Imagine trying to look up research papers. You won't be just searching for the new name, you'll be searching for the new name and every single name it was ever called to find all relevant research. You'll literally still be dealing with it every time.

It's come up a few times with insects. Name changes and suddenly research papers get missed/ignored because they still used the old name and vice versa.

And frankly, it's a name. It's just a word we attached to something to identify it. If that makes you emotional, maybe don't be in science?

The words have negative meanings because we acknowledge the meaning. Most people don't know "affra" is a slur and never would have even considered it until someone else loudly goes "hey! That sucks!". If you just ignored it, it literally wouldn't exist. It's going out of its way to point out something most people never even consider.