Ah, that's just the default. I see. I was wondering what they were smoking there that makes a lot more sense. It's a very peculiar choice, EXT4 is pretty good for most use cases, when you need XFS there are few alternatives but the performance issues make it a love/hate relationship and I really would not want that on my machines by default.
One problem with colocation is that a lot of the hosting providers I work with simply do a default re-image which will use whatever the OS comes with as standard. So chances are those will default to XFS and good luck getting rid of it then. (No phyical access to the machines.)
Not to be an apologist, but you can work around the performance issues in XFS, and a good amount of them were patched up in recent kernels. Disabling write barriers, delayed logging, and an independent journal device make it as fast (or faster) than ext4. But ideally you should stick to what you know and have already tuned unless you need some feature from XFS.