If you’ve read a self-help book, been to therapy, or attended a motivational seminar, you may be familiar with the locus of control concept. Someone with an internal locus of control is self-directed, whereas someone with an external locus of control sees himself as being at the mercy of outside forces. Folks with external loci of control are perpetually tossed hither and yon by the whims of their peer group, corporations and the government, or society as a whole.
In light of those definitions, you might expect control freaks to have internal loci of control. The reality is that having an external locus of control tends to make someone a micromanaging meddler.
This dynamic may seem counterintuitive, but it makes sense when you consider that people with external loci of control tend to lack self-discipline since they don’t think regulating their own behavior is possible. Their lack of self-control unleashes chaos in their lives, and the only way they can conceive of to mitigate the damage is to control everyone and everything around them.
Like most things in life, it's not purely binary. For alcoholics, the mere presence of alcohol causes them issues. Simple common courtesy dictates that one be circumspect on what one discusses around a man grieving the loss of his wife, son, or father. We can't get away from the fact that some things we see, combined with our experiences and memories, will cause pain, fear, sadness, joy.
In the end, it's more about where the responsibility lies in how we deal with the problems and emotions we cannot avoid. Is it something we can and should learn to deal with? Or is it something beyond our control that drives us unthinking before it like a leaf before the wind?
In the latter case, if they eat a dessert while on a diet, it's because you ate that cheesecake. And so it's your behavior that needs to be fixed, so that they are not tempted, you can't be a bad example, you can't make them feel bad (as in the "body positivity" movement). These are the kind of people that view you telling them "no" to a demand as an attack upon them.
It's not our responsibility to make other people happy, even if it were possible to do so. It is possible to objectively cause harm, but it similarly cannot be our responsibility to avoid causing bad feelings about weight, gender, or any other issue, especially at odds with reality.
This is also less of a problem in people with firm boundaries.
But then, liberals and cluster B's don't have those.