The issue that I take with this mindset is really it's ignorance of what the word 'theory' means in scientific terms. A scientific theory has been repeatedly tested and repeatedly corroborated, using the scientific method of observation, measurement, and evaluation of results. It's not some mythological tangle of ideas governing the morality of others' behavior that literally has zero evidence to back it up, and equating the two is more than a little blindsided in my opinion.
I mean, gravity is just a theory right?