That’s exactly why there are so many more terrible people in men’s friend groups they think are innocent. You don’t take any time to see who this person genuinely is that when you find out something crazy they did it’s a shock, but you know better because you overlook things. I’m not saying know his SSN but at least know him outside of a few things?
You seem very detached by your first point and I’m sorry you think that way. That second point, however, is exactly what women try to do, most of our best friends can’t remember when we became friends or why, just that we share something and like to hang out. There’s no ulterior motive for us, just like for you. However, when you know someone deeply, I imagine it’s easier to drop them if their personality is crappy. To know someone casually, dots don’t connect and it seems like a one-off