You can make that same argument for Opium derivatives, but not sure you want to. Endorphins ("endogenous morphine") are endogenous opioid inhibitory neuropeptides.
Endogenous opioids are another example of compounds that are also not similar to opioid drugs.
Endogenous opioids are small peptides. Morphine and derivatives are small molecules.
Cannabinoids are three ringed small molecules whereas endocannabinoids are fatty acids.
Structurally they are not the same.
This is in contrast to drugs like amphetamines and hallucinogens which are in the same structural class as their endogenous analogues, indoleamines and catecholamines.
The whole argument of the naturalness of drugs making them good is a variation on the same liberal argument of born this way.
In fact, plants evolved these compounds as a self defense mechanism. As toxins meant to keep animals from eating them.
The fact that humans are able to take toxins and poisons and use them medicinally and therapeutically does not change the fact that they are toxins and poisons.