It seems doubtful now that affordable housing is the core issue surrounding the homelessness crisis. While it assuredly plays a role along with addiction and other issues I think it's more a symptom of a society facing a crisis, with many fracture lines but with needs few want to truly address.
Allowing people to defecate and urinate on the streets with impunity, is not really doing anything.
Are you saying we should punish those that defecate and urinate on the streets?
What do you mean that allowing this behaviour "does" nothing?