We know from intervention research that the factors I mentioned are operative. Thus, when folks say that they are not influenced by them, I take that with a grain of salt.
They may not be liars (but I do think lots of internet talk is bluster) but I'd bet that faced with a real incident where the person doesn't meet certain of the tests I mentioned or the risks were high, lots of the absolutists won't jump in.
Of course there is no way to test an individual from the group. Listening to a tactical trainer who once was a police chief, he mentioned that he could tell you who blustered but always was late to arrive on a help the other cop call.
I have no reason to think that some posters are not the same.
I explicitly state that an intervention decision by me is going to be complex and based on a lot of factors. Those who stated they absolutely would help anyone with no thought of risk to self or consequences to family are very suspect in my eyes based on research and listening to lectures from responders.