They have indeed banned the sale of hatching eggs - they are explicitly named in their 'live animals policy' as prohibited items.
Mentors can only advise on Ebay policy, not the reasoning behind their decisions. To be honest, I think it is unlikely that any Ebay Customer Services advisors could explain the reason behind this change.
You will have to find somewhere else to sell your hatching eggs.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)
