you are quoting my quotation of Miles Mathis. i don’t endorse his theories, and even he is not really saying “calculus is straight-up wrong”. his argument is apparently more subtle than that, though i have not yet understood it.
as an aside, you certainly do not need infinitesimals or infinity to do calculus, unless by those words you simply mean “small enough” and “large enough” for a given purpose. see the entire discussion at https://forum.freecapitalists.org/t/anyone-frequent-any-science-or-physics-forums-groups/16410/117, complete with many visual aids.