Both are true, but Marx's quote references revolution as a social and historical phenomenon and Che's quote talks about an individual's approach to revolution.
does a revolution stop being possible when the soldiers that oppose it have tanks or planes or submarines or chemical weapons or even nukes or missiles, clearly not. why would "autonomous" weapon systems be any different, they still have to be made and maintained by someone and they still have to be directed by someone. Drones and "robots" are just new weapons there are still people behind them. And if u are warried about ai that can potential replace people in all those roles 1 there is no actual ai and we are not even anywhere near actual ai (like there is nothing in the horizon that even indicates that it could be possible) but even if we were an ai that can do everything humans can, can well... do everything a human can including being mad about its own material conditions. Besides if anything a technology that allows for capitalists law to be upheld by fewer people under normal circumstances, pushes more people into a position where they would benefit from a revolution.
Also why would it even matter the red army didnt win because the white army felt bad about what they were upholding, Fidel's march on Habana didnt succeed because batista's fascists goons felt bad about what they were doing it.
artificially intelligent killer drones owned by the bourg?
With the power of kung-fu fighting.
Maybe it's best not to make up sci-fi scenarios and instead work with what we have here and now, or at least with the predictions we can make solidly regarding the immediate future. Sure, Marx's analysis is not independent of all contexts, but to determine that you need your context to exist in the first place.
its not sci fi anymore. The AI isnt necessary when 1 person can supervise 100 sentry turrets strapped to a remotely controlled sled. These things exist now. Luckily so far theyre only used for guarding military bases and not putting down strikes.