If you were 'pulling' on your hair then again it's your technique that is at fault not co-washing itself. Haircare 'experts' advise us to be gentle with our hair especially when detangling or when hair is wet, curls or not co-washing or not. There is a huge difference between the amount of gliding massage required to cleanse and vigorous massage or 'pulling' (your words).
I have not questioned your experience in fact I postulated there may be underlying inflammation, I have questioned your unscientific assessment of the root cause as being overly moisturising the follicles. I am hardly a blinkered advocate of co-washing for all, I have said in a number of threads that it doesn't suit those with all dermatological issues or with fine/ thin hair. What on earth a science-based discussion has to do with how 'well liked' you are I have no idea, what a strange comment.
It's not illogical, you being ignorant of it doesn't mean it is not commonplace. Using foaming surfactant shower gels or traditional bar soap and foaming face washes is FAR from universal, spend some time working in pharmacy or dermatology or on skincare forums. There are studies demonstrating the negative effect of these on skin and/ or hair, especially those with pre-existing damage - be that genetic or due to chemical processes (hair).
Plenty cleanse their skin with oils sometimes using lengthy massage and enthusiastic rubbing (see Oil Cleansing Method), which interestingly CAN cause problems with irritation and inflammation in the skin but not, AFAIK
, hair loss. Plenty more use cleansing lotions or traditional cold cream on their face twice daily with very similar formulations to hair conditioner, others wash their entire body with products like aqueous cream or products like WEN body cleansing creme. Some who are seeking skin lightening undertake lengthy and complex daily 'exfoliating' routines with a series of chemical laden creams, professional athletes having regular deep tissue massages. THEN on top many of these groups pile on another layer of moisturiser or body lotion containing yet more fatty alcohols and cationic surfactants.
I don't believe true 'overconditioning' of hair is pseudoscience, it refers to keeping the hair wetted for long periods which can partially unravel the structural proteins and loosen the bonds making hair feel soft and mushy, weakening the curl pattern. Some like that effect, for example ladies who 'baggy' overnight. The opposite effect is seen with magnesium sulphate which reduces the water in the core of the hair, tightens the bonds and curl patten.
The possible benefits of CO-washing for dead hair is a different animal to the benefits or detriment for living skin (esp. follicles) which is what we are discussing in this thread. Certain groups of surfactants, especially from the anionic family, are proven to damage skin and hair: co-washing aims not so much to directly improve
the health of hair (since unlike skin it is dead) but to maintain
more of its natural protective and strengthening structure for longer after it comes out of the follicle. To see how that works you don't necessarily need one study you bring together the results of many, for example the effect of different pH on the position of the cuticle, which harsh ingredients can dissolve or attract structural lipids like 18-MEA and ceramides, the effects of cationics and fatty alcohols on combing friction.
The effect of cream or lotion products containing a wide variety of ingredients that you will also see in hair conditioners has been studied extensively for both efficacy AND safety on the skin. As a result some are known allergens particularly proteins, fragrances and preservatives. Others can alter the skin's permeability with acute or chronic use, strengthening or weakening it. See the Journal of Cosmetic Science, papers on corneobiology or corneotherapy especially those by the late Albert Kligman and his associates, any of the reputable peer reviewed dermatology journals.