Perhaps that is the complaint here - and asking for academic background is an argument from authority...
- it cannot be detected the way you detect your phone in your hand or see light so your definition of detection seems to escape the basic premise of dark matter: its ability to avoid electromagnetic force, and also,
- we have detected it through gravitational anomalies
With the DM effect, we ONLY see gravitational anomalies as you said. Though DM may very well be the reason, it does not automatically mean it MUST be some matter we cannot see
No it isn't. It isn't even an argument of any sort. I think most reasonable people would interpret that as an attempt to gather evidence to support applying a heuristic filter to the question of "is it worth my time to continue engaging with this person or not?"
Except for all the ways we have to detect actual matter (i.e. gravitation) that fits its properties.