Obsession with fish pain

Like many controversial topics, fishes' ability to feel pain has both been supported and brought in to question by a variety of studies. A simple google search will bring up opposing arguments from studies done in just the past couple of years, and the only real consensus I could find was that they cant feel specifically in the same way that humans can. Why is there such a disagreement on this topic? are fish put through more pain than our usual livestock? Is there so little care for this topic, that they cant fund a proper investigation, or can any study can get away with saying what they want without fear of a public backlash? Perhaps it is because of the agreement that this problem occurs. People can't agree on the definition of pain, is it the ability to feel when, and tendency to subconsciously react to bodily damage? or must it be processed the same way as humans and similar animals to truly cause suffering? I find it fascination that a creature many hold in such low regard can make us question what it truly means to feel something.