I'm very into combat sports and I've seen this argument a lot. It makes no sense to me. Watch some bareknuckle boxing, people are not holding back and just break their hands all the time and knockouts happen much earlier. The newest science on CTE makes it seem like accumulated small damage might actually be worse than periodic large damage, so the only argument in favor of bare knuckle boxing is that you get knocked out so quickly that you don't get a chance to accumulate damage.

8oz gloves seems to be a very reasonable middle ground to me.