Perhaps their son/daughter loves them more than you love yours?
If you love your parents, you should spend your money to support them, not rely on the society. I believe when their parents applied for immigration, their sponsors, guess their children must provide the proof that they could and will support their parents financially, so that they would not become the burdon of the states. Ironically, they will suck up the states as soon as they land here. What's this? Isn't this a kind of cheating?
OTOH, there are thousands on legal non-mmigrant workers who payed taxes for several years in US and went back to their home country. In their cases US governement is stealing Social Security and medicare Benefits from them. Their children won't be going to US schools either. Main reason Social security is bankrupt is because America has aging demogarphics. Over 65 is the largest growing age group in US. There more people claiming benefits than people paying into it. Without young immigrants, US will soon be nation on crutches. Also, it is becoming more expensive to have and raise children in US, hence the decline of young population.
Get your facts straight before you put your feet in your mouth.