I think one of the problems in political discourse is that we have a tendency to oversimplify complex issues by mapping a wide variety of disparate viewpoints onto a small number of political factions.
I think this the result of our tendency to be tribal creatures first and rational creatures second. The primary distinction is whether you're in my in-group or my out-group. Rational discourse is secondary and also optional. Especially in political interactions, people will generally scrutinize you for tribal markers to find out if you're one of the Good People. This may take precedence over other concerns, such as trying to accurately understand your point of view.
Expressing political ideas serves as a flag that signal group affiliation in addition to being a contribution to public discourse. People may emphasize these functions differently. A lot of politicking revolves around strategically choosing where to plant your flag keeping in mind how other coalitions will react to you. For example, if your coalition is unpopular, you may choose to rally around an idea that most people will agree with. This forces your opponents to deny the stance, which goes some way towards delegitimizing them. Alternatively, if your cause is generally viewed as just, you may choose a slightly unreasonable idea as a flag, so you can more easily identify and target people that sway from the orthodoxy. (I think this is one of the reasons why social justice and nerds often don't mix.)
In some cases, the same flag can match coalitions that don't fundamentally have much in common, but that come to the similar conclusions on highly visible issues. For a group, this creates the choice of whether to explicitly distance itself from nearby groups at the cost of losing coherence and visibility in public discourse, or to risk being associated with those groups.
I think an example of this can be found in libertarianism, where very different motivations can lead one to argue libertarian viewpoints, but the general public generally sees a large ideological blob. One the one hand, libertarian ideas derive from a position that seeks freedom from coercion, a classical liberal project that aims to establish a society is held together by win-win cooperation and only resorts to coercive methods in extreme cases. Such a viewpoint is compatible with welfarist ideas as long as they have an opt-in component. As an example, one may imagine a libertarian charter city that uses European style welfare models, but where people are free to leave, limited only by contractual obligations they explicitly agreed to. On the other hand, libertarianism can also be an expression of the concrete desire to abolish existing coordination mechanisms and sharing arrangements. These two kinds of libertarianism, one which seeks to rebuild a strongly cooperative society on the basis of non-coercion and the other which would prefer to see society reshaped along less cooperative and more individualistically competitive lines, are very different in nature, yet look a lot alike when seen from outside.
I think a similar thing is happening with neoreaction and the alt-right. Neoreaction could be a post-post modernist rediscovery of order and structure that is informed by both the failures of naive, rigid modernism and the self-serving and dangerously ineffectual dispersions of post-modernism. The alt-right on the other hand is a more old-school nationalist or ethnocentric movement. From the outside they sure look a lot alike.