The thought of Aksel morphing into another creature was scary to them. It left them to wonder if he would be change beyond recognition just from his physical feature or mind as well. Because it was nowhere mentioned even once that the change and mutation was only a physical thing.
No one ever knew the 'before' period of these Exters and therefore how much they had been altered 'after' had never crossed their minds but that wasn't the case with Aksel. They knew this man inside out and about all his ideologies and nature, if those were to mutate along with his physical features then would Aksel even remain the Aksel that they knew?
These thoughts sent shudders through their body as they each wondered about it on their own not daring to speak loud about it. They were afraid it would become true if woven out in words for the world to acknowledge and establish.