For me, not using/tossing out the microwave is about avoiding radiation and the relationship I have with my food and preparing it.
Studies have shown that microwave heating can trigger chemical changes in food, from nutrient loss to byproducts you probably don’t want in your body. Not only that, but it separates us from the process of preparing our food and our sensory experience-leading to a less enjoyable experience. When we don't interact with our food in a mindful way, we often don't digest and absorb all the nutrients well.
Lack of Nutrition
Microwaving reduces nutrients in food. In some foods, like broccoli, the nutrients can be reduced by as much as 97% by microwave cooking. Microwaving garlic for only 30 seconds can destroy all of its cancer-fighting properties.
Food sold as microwavable meals are full of highly processed ingredients that have been developed to heat quickly in a microwave. They lack nutrients, are full of harmful additives, and don't taste great.
Microwave ovens work by rapidly heating up the water molecules in food. They often cook unevenly, so you end up with very hot spots and lukewarm-to-cold spots. The reason we cook food is to kill the microbes. Uneven microwave cooking doesn’t combat all of these microbes and you can end up with bacteria.
Harmful Effects
Microwaves emit radiation into the home. There is some disagreement about what is a safe level of radiation. Either way, radiation does leak from a microwave oven. This is particularly a problem with older microwave ovens, even when not in use.
The plastic containers used to heat microwave meals have been found to release toxic chemicals, such as BPA (Bisphenol A), PET (Polyethylene terephthalate), benzene, and xylene, into the food. These carcinogens are then absorbed into the body.
Most varieties of microwave popcorn come in a bag that contains a chemical listed by the EPA as a carcinogen. The bags are lined with PFOA (perfluorooctanoic acid) which is the same toxic chemical found in teflon pans. It stays in the human body for a long period of time and has been linked to infertility, cancer, thyroid toxicity and memory loss.
Microwaves can change your heart rate. The effects of the 2.4 GH radiation produced by microwave ovens can instantly affect your body. Studies have shown that the levels of radiation emitted by a microwave can affect your heart rate and heart rate variability.
Food Tastes Better When Cooked Slowly or Minimally
The fast cooking of a microwave oven doesn’t allow time for flavors to fuse together. Cooking slow and at lower temperatures preserve and enriches flavors in food.
The texture of food is not the same when cooked in a microwave.
Taking time to prepare food and mindfully eat is an important part of a healthy lifestyle. Microwave ovens promote a quick-eating lifestyle which is counter to everything pleasurable and healthy about mealtime. We also don't digest our food as well when we eat fast.
ANOTHER INTERESTING OBSERVATION: Have you noticed the glass plate that you set your food on inside the microwave is the same symbol for radioactive symbol?
This article in the NIH database reviews how microwave heating impacts food quality and safety: https://pmc.ncbi.nlm.nih.gov/articles/PMC4440565/
Radiation effects on male fertility:
https://rbej.biomedcentral.com/articles/10.1186/s12958-018-0431-1