Well, that's a bold statement. Let me clear things up :).
When those people say "they prefer the old sprite" they don't mean it like they hate the new sprite or they prefer the old one because they prefer the visuals of it, but rather they prefer it because they are emotionally attached to it, if you know what that means.
Simply put it like this. you had your very first plush that was gifted to you 2 years ago for your birthday and within the course of those 2 years you built a strong connection with that plush and for your next birthday that will come in a few days, your parents/friends planned to get you a new plush, one that is very identical and much better looking than what you got 2 years ago. would you ever feel the same way towards the new one?
I came to a realization that these people are just afraid that those connection/feelings they once felt will be lost and they want to continue the story with those feelings intact that's why they want the old sprites because those are the ones that keep those feelings alive.
Sometimes we have to consider putting ourselves in others situation and try to understand them and not just think of what we think are the reasons why they act this way.
the annoying shit about this issue is it hasn't been stop ever since the changes were made. And since somebody who is kind and considerate enough to make something that would help the others, I just hope this issue will be demolished for good. I think it's a win-win situation both for the VN and the its readers.
Just so you know, I personally like the new sprites more than the old one because it is more accurate in the CG's. and I have learned to love the new one over time.
It feels weird arguing this with someone you know :P... hope that doesn't change anything lol