This has nothing to do with conditional or conditional help, or help at all. You feel compelled to fool yourself into believing you're not being exploited, but you're the only one believing that nonsense. You're dealt with like the mark in a con, and not exercising any common sense does not make you more pious, just an easy mark without self esteem.
The people that leech off of you are not the ones who need it the most. They are just the ones that don't mind profiting from less than ethical and moral means.
It's ok to be yourself around those people, to let down your proverbial guard, while having appropriate boundaries and not being exploited ... But over focus on who exploits and who is exploited blah blah blah ... All of that is quite toxic. It can make you just as miserable as the people you're accusing, if not more. And if you see every interaction this way, it's only a matter of time before you start seeing potential exploitation where it doesn't exist.
I'm sorry good sir or madam, I stopped reading here.
In my personal life experience with abusive people, I find it makes me want to be more in favor of unconditional help for others, not less. Though I have experienced the urge to want to help people less, which you seem stuck in, and I was formerly stuck. I think it's a stress response. It creates a lot of anxiety to keep sizing people up for how they're going to screw you, instead of just accepting them and treating them well. (Yes, there is a difference between treating them well and letting them abuse you.)