Is there something wrong with asking for a source? When they call the other person's claim propaganda and are trying to state their own as fact, they should be

Is there something wrong with asking for a source? When they call the other person's claim propaganda and are trying to state their own as fact, they should be able to back it up with something. I'm not going to blindly take something like that as fact, especially considering recent (but also historical) events. (Might also not be relevant but I will clarify anyway: I am not American)