Paleo is not bad for you. It just has a bad reputation because of the name and the false belief that it's a good diet because it's how our ancestors ate and so we should too.
Paleo is all about eating high quality meats (grown without hormones and antibiotics, and grass-fed), high quality fish, a plethora of vegetables and fruits, eggs, seeds/nuts, and healthy fats. It's about cutting crap out and focusing on nutrient dense foods. Some people cling to their relationship with grains, but it's not a necessary part of our diet and many of the proteins in grains are problematic because it takes longer for our bodies to break them down comparatively, and this can lead to immune responses in the gut because the body wants simple amino acids and can get a bit dysfunctional and "angry" when exposed to too many proteins which haven't had time to break down. Because the gut is the entrance to our body and comprises approximately 70% of our immune system, as well as hosting a complex microbiota which basically commands us via the gut-brain axis, it is imperative to keep our guts healthy and inflammation free.
This is why so many people with autoimmune disorders attempt Paleo or similar diets. It's important to note that restricting too many foods in an effort to reduce autoimmune response in the gut can lead to reduced food tolerance. This happens because the disease process still exists in the body despite limiting diet, and this hyperactivity of the gut can result in attack on more simple amino acids in other foods, such as vegetables. For this reason, extremely restricted diets, such as the AIP (Autoimmune Protocol) diet which restricts much more than the Paleo diet should not be continued for more than 6-weeks and should be used more as a quick fix for severe gut inflammation/autoimmune disorders. Furthermore, diets such as these should be looked at as lifestyles rather than restrictions and should be paired with exercise and mindfulness, thereby treating the body as the complex interconnected entity it is.
End nerd speech.