The facts quoted can be based on legislation or reliable statistics, or on personal experiences by the poster, or on what they believe is true because someone has told them they read it in an online rant (by a bigot).
Contradictions of the posted facts can also be from official legislation published by the agencies that actually deal with the people in question, or from personal experience of talking to them and hearing their stories, or from pure resentment that someone may be getting away with something that the poster isn't, or from complete ignorance of what is going on around the globe.
The world is changing. It is getting smaller every year as communications become more instant and troubles as well as material goods are exported thousands of miles to be shared by the lucky and the unlucky. Some of the unlucky - in all senses, in their freedom or lack of it under a corrupt or draconian government, their food when their climate becomes less and less capable of growing anything worth eating and they can't afford to buy from the lucky ones who are doing OK and wasting theirs, their health if they can't pay for treatment, their very chance of life for themselves and their children as war kills and housing is destroyed - if they can manage it, they travel to where the lucky ones live to throw themselves on their mercy.
There they find that a good proportion of the population believe that they are all there under false pretences, and no-one should be given even enough to keep them from starving or freezing, or rescued from drowning if their boat founders. What a case of "I'm all right Jack. Pull up the ladder."