This is, unfortunately, the bane of microaggressions. A lot of inappropriate behavior slips under the radar: anybody who calls it out is accused of making too big a deal of it. A man might be slightly more effective than having you call it out, but it would have to reach a fairly high level of impropriety.
It may help when somebody says, "Hey, X was talking, and I want to hear it." Fixing it immediately helps more than a talking-to afterwards: the odds are good that they don't even remember interrupting you, and if they're not intent on taking it to heart, they won't. They'll often feel the callout was a disproportionate harm, way worse than whatever it is they did.
But a lot of men won't even notice. I've missed a lot of them, or rationalized "that wasn't so bad" and quickly forgotten about it.
You're correct that we should focus on minimizing and preventing harm, but it's just really hard.
It may help when somebody says, "Hey, X was talking, and I want to hear it." Fixing it immediately helps more than a talking-to afterwards: the odds are good that they don't even remember interrupting you, and if they're not intent on taking it to heart, they won't. They'll often feel the callout was a disproportionate harm, way worse than whatever it is they did.
But a lot of men won't even notice. I've missed a lot of them, or rationalized "that wasn't so bad" and quickly forgotten about it.
You're correct that we should focus on minimizing and preventing harm, but it's just really hard.