You still abused an exploit which is still bannable. The exploit in question abused a vulnerability in Plan which clogged it up with bogus data
Except it's not an exploit. It's a feature. Mojang allows specifying hostnames in their protocol. If this was not allowed by Ryan, there was no way Veast could know.
The only way this could be changed is:
1. Installing a plugin that allows connections from only TotalFreedom domains
This would make it annoying for people to set up domains that lead to TF, such as tf.fo and others.
2. Trying to resolve hostnames for people who connect with different hostnames
While this would patch connecting with nonexistent domains, this would lead to another exploit: Lagging the server by connecting tons of accounts with random domains. It also wouldn't really fix anything, because people can just register domains and join with them.
3. Completely turning off the Plan feature that allows people to see the hostnames used to connect to the server
This is likely the best solution. It would harm no one, and it would make connecting with custom hostnames do absolutely nothing.