> enables the "homeless lifestyle" without any accountability
You mean by not having public housing?
> Homelessness is - for the most part in San Francisco - a choice and/or a result of mental illness and drug addiction.
It's obviously not a choice. It's also not the result of mental illness nor of drug addiction, at least for the most part, as people suffering from mental illness or addicted to some drug also don't want to be homeless and stuck on the streets. And while they are somewhat more likely to lose their house due to mis-managing their life - it is much much more likely to happen when they have no social support: Medical care-givers (no such thing by default in the US), neighborhood/community associations (not much of that in most cities), families etc.
> where are my rights as a lawful tax payer who cannot bring his son to the park without risking his life by stepping on a needle?
Your right is not catered to by social institutions, and municipal ones in particular, who are acting as though homelessness should be addressed by suppressing/harassing the homeless rather than ensuring people have homes.