The fallacy is that a direct personal experience of one person's dishonest behaviour trumps a financial and economic system which relies on similar actions on an industrial scale.

One dude pretending to be crippled is much less socially destructive than an asset-stripping hedge fund which loads up multiple viable businesses with debt and then kills them.

The difference is the former is still relatively powerless, while the latter can be responsible for multiple instances of homelessness.

So it's not a question of "help" - it's about making sure that homelessness is an absolutely exceptional situation, not the systemic default for anyone who finds themselves on the wrong end of the value creation process. As well as the mentally ill.