Sentence:  Their core belief, unsupported by evidence or logic, is that homes are unaffordable because investors drive up prices. / Australians for Affordable Housing appears to think that <WSD>nobbling</WSD> investors will strike a telling blow for first-time buyers: remove negative gearing and increase capital gains tax, and homes will be affordable. 
Meaning of the word marked with <WSD> tags:  To injure or obstruct intentionally.