the criticism of argument from authority is really only valid for logic-based arguments (which only exist in math). In nearly every argument online, the topic is not logic-based, but more a combination of fuzzy reason and rhetoric. In such situations, we normally allow for some prior belief that people who obtained education and have worked in an area have some level of expertise that makes their arguments carry more weight. While you can argue whether this makes sense, it certainly seems reasonable to me- although I still apply skepticism to expert opinions.
I think you need to make insightful points for that. Having credentials is not a requirement for having insight, although they are sometimes correlated.
Nope. In order to be upvoted by an audience of highly techincal readers, I would hope that all one needs is to make a strong argument, or provide something interesting, or otherwise of value. Credentials can be a shortcut/filter to finding something of value. Someone may reasonably choose not to spend time reading something from someone with no credentials, under the assumption that most of everything is garbage. But, after having chosen to read it, the credentials no longer have any bearing. It's either good or it's not.
