My girlfriend and I were having an argument over something that her female friend had said about me, which I found rude and displeasing. My girlfriend responded to my complaint by saying "What do you want to do, bash her up?" She thinks this phrase is normal, but for me, there's something inherently wrong about it, especially given that the implied meaning is a guy (me) beating up a girl, and even if it was meant to be an ironic statement. Am I getting too sensitive over what is perhaps just a harmless idiom, or should I stick to my gut feeling?
I picked up my English in North America, whereas my girlfriend did in Malaysia/Singapore, and so there's a good chance that it might just be a cultural difference, but for me that doesn't change my feeling that it's offensive.