I am not sure what you are arguing against.

The original post to which I responded argued that homelessness has nothing to do with the 'survival of the fittest'. I argued two things. First, that it does insofar as capitalism is based, structurally and psychologically, on the transformation of humans into commodified labour to be sold on the market. Second, that the welfare state is an attempt to try and offset the human cost - deprivation, precarity, unemployment, exploitation - of the marketisation of social relations.

In response to what you said.

(1) 'Competitive impulses are not capitalist'. I never mentioned a 'competitive impulse'. I made the trivial claim that, (a) economics is one sphere of human life among others, and has no necessary priority over them; (b) that humans are moved by more than material self-interest. Both of those claims are compatible with the idea that humans are generally, and to varying degrees across history, 'competitive'.

(2) 'There is no evidence or indication that competitive impulses change as a result of changing or eliminating laws that provide people security of property and contract liberty'. You are reifying human psychology. Humans do not possess fixed and determinate 'impulses', apart from for simple objects like food, shelter, water, and sex. Humans are distinguished from other animals by their capacity for non-genetic learning. We create cultural meaning through language, art and social practices. These accumulate over time. Ultimately this dominates human behaviour and history. That means that you can rarely explain complex social behaviour by reference to fixed features of human psychology. We vary over time according to our social conditions.

The general idea that humans manifest the same competitive behaviours regardless of social conditions is comprehensively refuted by history. Do you really think pre-historic tribes, fifth century BC Sparta, and feudal Japan instantiated the same competitive dynamics as modern capitalist societies?

(3) 'No I'm saying that to the extent that they do try to maximize their own material interests, that will not change by changing the laws relating to private property rights.'

This is very vague. 'To the extent to which they do try to maximize their own material interests' leaves unstated how and to what extent humans maximise their material interests.

In response to the substance of your statement, let's imagine two scenarios:

Scenario 1: 'X' has to work 50 hours a week for the means of survival and, if she fails to do this, becomes unemployed, or suffers health problems, she faces death.

Scenario 2: X works 36 hours a week for a legally mandated minimum wage. If she is fired she is entitled to unemployment benefits. If she falls ill she has access to healthcare that is free at the point of use.

I take it to be patently obvious that X in scenario 1 is moved by material self-interest to a greater extent that is X in scenario 2. For in the first scenario it is a question of survival, whereas in the second case she has the time, ability and security to significantly give herself to extra-economic activities - culture, politics, morality and religion, society and family.

P.S. 'contract liberty' is a wonderful euphemism.