The claim that objects must be larger than the wavelength of light to be directly visible is refuted by numerous super-resolution microscopy techniques and near-field optical methods capable of imaging nanoscale objects much smaller than the wavelength of light.
While classical optical theory sets a diffraction limit around half the wavelength of light for conventional microscopes, modern physics and optics have developed numerous super-resolution techniques (such as STORM, MINFLUX, SIM, s-SNOM, and hyperlenses) that routinely image objects much smaller than the wavelength of light. The claim is therefore definitively refuted by empirical evidence.