You're entirely wrong. Einstein disregarded the idea of space as an ontological object early on and showed the Lorentz equations could be derived without the assumption of an ether. He began his paper with,
"We will raise this conjecture (the purport of which will hereafter be called the ``Principle of Relativity'') to the status of a postulate, and also introduce another postulate, which is only apparently irreconcilable with the former, namely, that light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body. These two postulates suffice for the attainment of a simple and consistent theory of the electrodynamics of moving bodies based on Maxwell's theory for stationary bodies. The introduction of a ``luminiferous ether'' will prove to be superfluous inasmuch as the view here to be developed will not require an ``absolutely stationary space'' provided with special properties, nor assign a velocity-vector to a point of the empty space in which electromagnetic processes take place."
Later in life Einstein came back to an aether more often described as "Mach's Ether". On this he wrote, "But this ether may not be thought of as endowed with the quality characteristic of ponderable media, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it."
That being said, modern physics has all but done away with the concept of ether. Under modern quantum field theory, photons are the carrier particles of the electromagnetic force. Gluons are the carrier particles for the strong nuclear force, while bosons are the carrier particles for the weak nuclear force. The graviton is the carrier particle for gravity. You'll also find that general relativity treats spacetime as a field
which does not necessitate an ontological entity termed "spacetime". Even moreso, under quantum field theory, these fields
find their effects mediated by ontological objects rather than an ontological entity termed "space".
So no, I think you're wrong to conclude that anyone who understands and buys into relativity must also believe in an ontological entity termed "space".