Frozen food is not inherently inferior to home-cooked food at all, given that you can freeze things you make at home without the universe imploding! I made a pizza the other day. Some of it is in my freezer now. It's not as good as it was hot out of the oven, but it's still a fine pizza considering I'd never made one before (future pizzas will be better). I used frozen spinach in the pizza because frozen vegetables are no less healthful or tasty (although there are some applications for which they are unsuitable, like roasting) and easier to keep around.

However, as a contingent, non-inherent fact about commercially available prepared frozen meals, they are often made with inferior ingredients (the details of the process are largely concealed from the consumer so this is likely to be financially worthwhile), designed for bland flavor profiles (to appeal to the broadest customer base), and loaded up with cheap tricks to make them desirable in spite of this blandness (inexpensive fat and starch and salt and sugar). The texture often leaves much to be desired as well.