What I see is that most of the "hating" or "not-bonding-with" comes from people who enjoy their Kalas and Ohanas. Thus, my guess is that this is about managing expectations: For most people, a Pono is a giant leap up in cost from what they have, so they are expecting an instrument that plays at least twice or three times as nice as an inexpensive one, and that's not going to happen, not even with instruments that cost way more than a Pono. This experience will give you a good feeling about the less expensive stuff you can afford, and that's perfectly fine: Why should you pay more for something that doesn't give you a lot more enjoyment than what you already have.
To me, it's the combination of some very little things that make Pono a league of their own which I would never compare to some of the generic "brands" you see on Amazon, including the aforementioned Kalas and Ohanas: Pono ukes are always made from solid woods, no tricking about calling their models only by a thin sheet of veneer, leaving away the important word "laminate". They only use wooden bindings and natural products for inlays, nuts and saddles, no plastic, "faux" or "pearloid". They are designed and supervised by a family that has been around and well-respected in the ukulele community for almost 30 years, who certainly know what they are doing and keep coming up with fresh ideas for interesting new models. They were the first to react to international regulations on Rosewood and Pearl and banish these materials from their lineup. They try to operate sustainable. They have their own production line in Indonesia, not just ordering from some ominous factories in China. Their tenors and baritones come with a truss-rod which you may never need, but it will provide stability for decades to come, when other instruments' necks will long be bowed and warped. Last but not least, I like their perfectly rounded neck profile and can tell you that is very similar to the ones of some high-profile custom builders such as LFdM, Beau Hannam, Jay Lichty, or Jerry Hoffmann.
Having owned about 12 instruments from Pono over the years, I have been very happy with most of them, playing them side-by-side next to the custom builds mentioned above. And here is where I get that very same feeling expressed above: Sure, those custom builds may have some more clarity or better volume, but some of the Ponos come pretty close at a fraction of the price.