I've heard this so many times but I disagree. 'Some men' would be more accurate as its clear that some may not have had much choice in their home countries but the majority? Have you carried out some form of survey?
Most of the foreign men that I know in Thailand, came or come following a divorce back home, I'm no different - 21 years ago my (UK) wife of 19 years left without warning - it turned out she'd been having an affair for years. I don't consider myself to be particularly handsome but I'd never had a problem finding an attractive partner back home - my ex was a 'stunner'.
Following the divorce I spent a year in the doldrums, approaching middle age and thinking life was over. I took a trip to Thailand. I regained my confidence and dare I say it, despite some relationship problems from time to time, I've had a much better time than I've ever had. The bonus point is, in the UK a much younger woman would not even look at me, in Thailand I had a choice and to a lesser degree (these days ????), I still have.
As an aside, my UK ex wife wasn't so lucky. She moved in with the guy she'd been having an affair with but he turned out to be a pervert who sexually and violently abused her and ripped her of most of the inheritance she'd received from her parents - that lasted for 2 years. We have a daughter so I still see her from time to time.........jeez, she's fat, everything's gone south and she's clearly made a bad decision on some form of lip filler/treatment. She now resembles a trout - a fat trout.