Streamers are performance artists. They usually own their streaming setups, and take donations or sell subscriptions for private streams. When you own your own means of production, your labor is not being exploited. Streamers do use platforms where capitalists own them, but streamers are not proletarianized by them, and it's closer to a business owner paying rent to a landlord. The subclass "artisan" is most applicable, and has been recognized as part of the petite bourgeoisie since Marx.

They also sell commodities they fashion, not their labor power for a wage or piece-wage, the commodity being entertainment. They are not selling their labor-power to their viewers, but the direct product of their labor-power, to which the platform takes a cut as rent.

Prolewiki's article on the Petite Bourgeoisie backs this up:

The petite bourgeoisie or petty bourgeoisie is the lower strata of the bourgeoisie, consisting of smaller-scale merchants, semi-autonomous peasants, small business owners, self-employed individuals with complete autonomy, and other business owners who own enough means of production to extract surplus value but not wealthy enough to subsist solely off that extraction, in contrast to the haute bourgeoisie. Therefore, they must also perform labour alongside their employees.

This coincides with the class outlook of self-employed people, who seek individual autonomy over collective bargaining (on average), whereas proletarian workers tend to come to the class outlook seeking collectivization. Artisinal reaction was covered by Marx. Independent artists struggle against proletarianization in a similar way to small business owners and other self-employed individuals. They can also be allied with the proletariat, due to their precarious social position.

Of all the classes that stand face to face with the bourgeoisie today, the proletariat alone is a really revolutionary class. The other classes decay and finally disappear in the face of Modern Industry; the proletariat is its special and essential product.

The lower middle class, the small manufacturer, the shopkeeper, the artisan, the peasant, all these fight against the bourgeoisie, to save from extinction their existence as fractions of the middle class. They are therefore not revolutionary, but conservative. Nay more, they are reactionary, for they try to roll back the wheel of history. If by chance, they are revolutionary, they are only so in view of their impending transfer into the proletariat; they thus defend not their present, but their future interests, they desert their own standpoint to place themselves at that of the proletariat.

• Manifesto of the Communist Party

I know I explained here, but the reason artisans like streamers tend to be reactionary is because, like the rest of the petite bourgeoisie, they stand to lose their autonomy. The petite bourgeoisie as a broad class collectively tend to value independence and fight against losing their autonomy.

This is the precariousness they have, whereas the proletariat has already lost their independence and so seeks collectivization. The petite bourgeoisie lose their independence through collectivization, but depending on the level of class struggle can actually side with the proletariat despite this against a common enemy, the haute bourgeoisie.

Yes, there are material reasons and they end up generally aligning with their own class interests