Except I never called Rainier a bully. I just said that banter made me feel like he was being a bully. That's it. Nothing more, nothing less.
I even acknowledged how they are supposed to have a positive relationship, and that this dialogue didn't fit with the relationship the game tries to give them to me.
Well, while it may, unfortunately, give the impression of bullying to you for whatever reason, it pretty clearly isn't that at all. I mean, what can anyone really say? I think everyone gets that that's how you're viewing this because of your reason(s), but you kind of make it sound as if other people are wrong when they're just trying to point out that this is really nothing more than a funny and decidedly impertinent question, as opposed to being bullying or bully-like behavior.
I'm sure that the writers were just trying to write some fairly funny dialogue, but I guess they weren't able to account for the more unusual reactions people might have to this particular banter. I'm just going to say that your take on this thing strikes me as being, well, on the unusual side. Being companionable/friendly most of the time doesn't mean you can't have the occasional ribbing and/or off-color questions. Blackwall does seem like kind of an earthy guy, and Sera can be crass and vulgar (but also entertaining), so I can kind of see it happening, especially if Sera is instigating.
My opinion is that the companions are all supposed to have different sides to their personalities. Sometimes they might display humor, vulgarity, kindness, sorrow, anger, etc. So yeah, maybe you have someone firing off a rude question/whatever once in a while or being a jerk, etc. To me, that makes them a bit more realistic, instead of forcing them to behave within a narrow set of parameters. *shrug*