The waiver gets filed to USCIS under DHS, so I don't think it's confrontational to them. The waiver also includes the other arguments as secondary: if applicant is inadmissible, she is still eligible for the waiver approval based on....
I did the K1 and IR1 myself, but I consulted the same lawyer who is doing the waiver at the time of the K1 denial and he had said to go ahead and get married and file an IR1, and I consulted him again right before the IR1 interview, and he said everything is good, your case is straightforward. Might he be trying to evade the liability of that?