Individualism has had its foes over the centuries, mainly because it is a bulwark against some people making use of unwilling others. If one is indeed a sovereign individual, with rights to one's life, liberty, etc., others are morally and would in justice be also barred legally from coercing one to do anything at all. Force against people could only be deployed if they started interfering with others, intruding upon them – assaulting, kidnapping, raping, robbing and doing other violence to them. Otherwise no one gets to mess with others unless they agree.
By now this is pretty much common sense in many societies except to those zealots who want to conscript others to their various projects, never mind the need to persuade them first. But one way this kind of prohibition of doing violence to individuals is being discredited is by distorting what individualism means. And a very common approach is to charge the position with "atomism," the idea that individualism means that people can live isolated from others, that they can be utterly self-sufficient and flourish that way.
Of course, no individualist in his right mind ever makes this claim. Some have made use of a version of this for purely analytical purposes, such as economic analysis. Doing this, however, does not mean that individualism implies the idea. Just because when people examine boxing or some other sport they do not pay attention to the marital status or artistic tastes of the athletes, it doesn't mean that these can be well understood without paying heed to those aspects of their lives only that their boxing, etc. could very well be. Most of us have our lives pretty much partitioned so that it is possible to examine it from various angles, focusing on just this or that part of it. One can be considered in one's role of a parent or friend or professional or citizen or lover of novels, etc. None of this means that one is only such a one dimensional individual, only that we can be understood in our various roles in life.
In economic analysis, for example, what tends to matter most is that we interact with others in the exchange relationship – we sell to them and buy from them and economists mostly focus on this fact. Sociologists focus on something else and biologists yet on others. None of this means that they believe we are nothing but economic or social or biological individuals.
To charge individualism with this kind of narrow-mindedness is a trick. Individualists themselves belie the charge in their very own lives, given how they are party to multiple rich relationships – familial, fraternal, professional, political, economic, artistic, recreational, etc. The point is not difficult to demonstrate in the case of every individual's life. And individualism implies only that these relationships exclude treating people as subjects, as the victims of others' imposition and coercion. But as to voluntary relationships, all those are perfectly compatible with individualism and are, indeed, demanded by it. Nothing else is more fitting for human relationships than being involved in them because one wants to be instead of because one is made a part of them by some others who presume to have the moral authority to decide how people ought to choose to live.
Nor does individualism mean that people are immune to critical evaluation by their fellows, that whatever one does is just fine and dandy. But if it is something peaceful – such as being fond of certain kinds of art or sports or technological gadgets – that is something others must acknowledge as immune to intervention apart from possible comment or advice or perhaps a bit of peer pressure. You want me to give up my love of jazz and join you in your love of bird watching, you've got to ask me and convince me.
Only if I intrude on you or someone else have I made myself the proper subject of forcible invasion.