Einstein himself was not a fan of cultural relativism and I believe detested the way his theory was applied to other areas outside physics. Much the same way that Darwin was not in favour of the way his ideas of selection were used by those advocating Eugenics.
On Absolute Truth....The Laws of Thermodynamics viz. Conservation of Energy, Increasing Entropy of the Universe plus Absolute Zero are probably as absolute as one can get. Gravity has been reworked with General Relativity to better understand Newton's Inverse Square Law however it has some problems at the quantum level. The jury is still out with respect to the fundamental Graviton particle (although odds are that we will likely find it). Chemical Reactions are largely manifestations of the electromagnetic force so I agree that the theory here is very solid. Absorption and Emission of Light can be described by Quantum Mechanics which at present seems to be well supported empirically. I would add to this list laws regarding both linear and angular momentum as well as certain symmetries that are consistent with conservation laws.
Special Relativity....Einstein's special theory broke the notion of absolute space and time. It also showed the energy and momentum require relativistic analysis. However in many ways its most perplexing outcome was the death blow for Simultaneity. Events that are simultaneous in one frame of reference need not be simultaneous in another. What does this mean? Observer 1 concludes that event A happened before event B. Observer 2 in another frame of reference concludes that the events were simultaneous (happened at the same time). Which one is correct? The answer - Both of them. This can influence, although I would urge much caution, our perception of events at least on a theoretical level for now.