Shame is also a choice. Shaming is a misnomer. A person has to choose to feel shame. You can "shame" someone all you want, but if the target has decided not to feel shame, tough luck. Shame is honestly only one person's fault, and that's whoever has chosen to feel it.
That is a oversimplification. The near instantaneous emotional responses we have to things aren't dictated by any one choice. We don't sense something then manually assign an emotion to it, it just happens. Ultimately, the emotions we feel in any one situation are the result of innumerable choices and situations we've experienced throughout our lives.
What we do have a choice in is how we respond to an emotion, whether we let go of or prolong it. Whilst that's a subtle difference, it's important. It's no easy task to let go of negative emotions. It takes a lot of practice, honesty, and self-reflection. It's a consciously learned skill which lot of people aren't even aware they could have. And even then, it's only through the daily application of that skill that we gradually reprogram ourselves to react to things differently. But that takes a long time and it's unfair to expect it of someone. Especially with regards strong, social, constantly reinforced emotions such as shame.
I used to have some rough anxiety issues. Through the aforementioned practice, honesty, and self-reflection, it is now a non-issue for me. That took 2-3 years and it's not like I never feel anxious anymore, I've just learnt to process it better. But if there was some sort of anxiety equivalent to body shaming, you can bet that it would still overwhelm me on some days.
At the end of the day, you are responsible for the emotions you cause in people. Whether you make them feel happy, sad, offended, angry, bored, frustrated, shameful, anxious, whatever. You can chose not to give a fuck about that - and sometimes you shouldn't - but that doesn't make you any less responsible for your actions