Unfortunately, the FSF isn't against firmware blobs, only against those updatable by a user.

From their Respects Your Freedom requirements page.

However, there is one exception for secondary embedded processors. The exception applies to software delivered inside auxiliary and low-level processors and FPGAs, within which software installation is not intended after the user obtains the product. This can include, for instance, microcode inside a processor, firmware built into an I/O device, or the gate pattern of an FPGA. The software in such secondary processors does not count as product software.

This means that proprietary firmware flashed at the factory and impossible to replace gets a pass, while hardware with firmware updates through blobs is rejected. Important security fixes (CPU microcode) or stability improvements will be missing if you can't update the firmware.