I dont have a problem there ...
If there's no nodes in Cryptopia's list, their wallet is going to have a hard time processing transactions, which is sorta important.
If you're part of the SUMO staff, I'd recommend you reaching out to the exchange soon and making sure they have nodes to connect to.
More seed nodes needed for sure but I found XMR had only 1 connection just as Sumokoin at Cryptopia, so I don't think exchange has any problem with that