Do you think all those fat ,old and lonely idiots who are marrying filipina bar ladies don't realize that they are only after a Green Card ?

They are just after a piece of poon.  Each gets what they want.

Many of them probably know deep down but are willing to take the risk in order to get some company... or in the hopes their experience is different and they really marry them for an honest reason.

Yes, but some do not care one iota, Daniel. When I was married to my second husband and he was in the Marine corps, he went to the Philippines for one year on deployment, and he slept around with ladies over there, and he divorced me to marry one who just wanted her green card. That marriage ended for him. Luckily I met a new guy who loves me and we are happily married. I feel like he got what he deserved. I don't know if he realized it later, but he made his bed, and lost his family over it.