well while phasing is simply just teleporting a certain part of ones body, you'd think it all the same.
with the juubi, think of it as being in an invisible tank but that tank is sentient and fights you.
unless you teleport the entire thing as a whole, more like forcing it into the wormhole, it can resist a rather small one that only transport a certain part of its body.
think of forcing someone to put their limb into a small hole, they will be able to resist.
however, if you shove them into the chasm or a rather big hole, they will less likely be able to resist.
It definitely is a plot no jutsu for both Obito's and Madara's cases and there's really no point to explain but if you really wanted an explanation, there it is.