I’m not clear on whether you think the drowning child argument is browbeating by nature, or whether you think that just this particular presentation of it is browbeating. (Your remark about retiring the drowning child implies the former, but another of your comments elsewhere implies that you can use the drowning child argument without browbeating people with it?)
Anyway, I don’t think it’s time to retire the argument, I still feel like I hear a lot of people cite it as insightful for them.
I don’t know if you’re even implying this, but the causal mechanism for altruism arising in humans doesn’t need to hold any moral force over us. Just because kin selection caused us to be altruistic, doesn’t mean we need to think “what would kin selection want?” when deciding how to be altruistic in future. We can replace the causal origin with our own moral foundations, and follow those instead.