Just a thought.
Could it be, that if you see a poor man it show's you that taxing and giving it to the poor doesn't work or at least not enough, cause if it worked there wouldn't be any poor people around? And that, liked you mentioned in you article, if you don't see the poor man, you're not confronted with that reality so you can think more ideologic about taxing and solving poverty through that method.

Another thought
Also If people are taxed, they might think the problem is already taken care of. The responsibility of helping poor people is now a problem of the politicians they voted for, not of them personally, (they've outsourced the problem so to say) so it's not their problem and responsibility anymore.
Everything they do to help the poor is playing the indirect political game (voting every 4 year) instead of taking direct responsibility. And who can blame them, this is how they where taught things worked.

In my opinion there is also a difference between:
Working on inequality, to resolve poverty
And working to resolve poverty.

(English is not my native language.)