1) Not all anarchists during this time were left "collectivist" anarchists. Though you're right that they were the most influential during the 19th century, anarchists like Benjamin Tucker, Max Stirner, Gustave de Molinari, Lysander Spooner, etc. all had some sort of "capitalist" leaning (Stirner promoted "Egoist Anarchism"; he's more known for his ontological views than political. Tucker was a "right-wing" anarchist of some sort. Molinari was essentially anarcho-capitalist. Spooner was a voluntarist, etc.). These movements of "anarchy with private property" are simulated by the anarcholiberal political group.
2) Even so, the anarcho-liberal political parties/bourgeious-dictatorships aren't truly "anarcho-liberal" (there remains a centralized "state"- or state-equivalent- organization). We could reasonably state that these were the James Mill or Frederic Bastiat-type "radicals" of the 19th century... or that some sort of large-scale security provider (Stirner's case: Union of Egoists, for example) took the place of the state.
As a voluntarist (Anarcho-capitalist), I have to say that the Anarcho-liberal movement (Anarcho-liberal, as far as I know, was a term invented for the game; however, Market Anarchism and Voluntarist existed during this time period) predates Rothbardian anarchism. The aforementioned Molinari was a "Market Anarchist" (close friend to minarchist Frederic Bastiat); Lysander Spooner was a voluntarist.
Except anarchism is an actual ideology distinct from the use of the term anarchy to refer to "chaos". Anarchism is a rejection of "rulers" (anarcho-liberalism is an objection to "rulers" that promotes the notion of private property). Un-colonized territories during this period had "rulers" (tribal kingdoms; 'states' in the ancap sense of the word) and in-fighting rebel groups doesn't accurately represent the philosophy of anarchism in the slightest.
This is miserably off-topic for a board discussing gameplay. Suffice to say, anarchist theorists have developed legal theories within a voluntary legal framework (some believe in the legitimacy of retaliatory force, a la Walter Block). Ancaps like Gustave de Molinari, Hans Hermann Hoppe, and Stefan Molyneux have attempted to address this concern in their legal theories.
Regardless of whether or not you believe such a society would work (vis-a-vis communism in the game), it deserves some representation in the game. Especially given that it's already represented as a "night's watchmen" government (not an anarcho-liberal stateless society). That is, the game already assumes that actual anarcho-liberalism is implausible, and replaced it with a "minimal state".
I'm fine with how anarcho-liberals are currently represented in the game. I'm a bit perturbed by the assumption that the default in anarcho-liberal revolution is a "Bourgeois Dictatorship" (note that this nowhere appears in market anarchist literature as an "alternative" to the democratic/monarchist/proletarian dictatorship states). I would think that naming the radical governments something like "Revolutionary Unions" or something (idk; find a term that may actually appear in anarchist literature; Security Providers seems too boring; "Voluntary Association" just sounds dumb); that way it can feasibly represent a non-state "director" of the "nation".