Then don't choose a server that has the Road to 70 Buff on. I joined as a first time FFXIV player (but not an MMO virgin) on a server with the buff, and was like level 28 before I did Sastasha at 15.

The reason they do this is to incentivise people to join those servers because they are quiet, it's a reward for NOT joining a busy server where all your friends might play, and you may have an easier time getting parties for FATEs and Raids. I suppose from a design standpoint, when they open a new server, or are trying to drive up the population on a new server, they want to have a suitably high population of people at end game and maxed out on their classes and gear, so that new players have people to guide them through the game. They offer you options, if this is not for you, then you may pick a server that is already established, and doesn't offer this reward.

It's not like they're forcing you to have a permanent EXP buff after all.