Well, while some of the complaints were real, the DoI was largely a propaganda document in the form of a lawyer's brief. It had some misleading elements and exaggerated issues.
And it tries to paint Americans in the best light, glossing over the myriad of things Americans did in the first place to cause the problems.
But, the flowery language is interesting, because most of the countries to which it was directed were...not liberal republics, anyway. The function of the Document was to entice foreign governments to support the United States, and it doesn't even seem intuitive to appeal to natural rights and revolution when your audience is a panel of monarchies opposed to the concept. It was probably useful for gaining popular support in England for the revolution, as well as in other countries, so as to exert pressure on their governments.