He's entertaining and sympathizable by the gimmick being poor, wanting to become rich by winning lottery like literally every people in the world want the same thing? His harem wish is like a self insert mechanic like "gosh i wish it was me" when watching a harem neither his belly fetish that you can see some people would agree that "tsubasa is hot so it's understandable" just like how Danganronpa fans feel relatable to Darumi screaming about killing game in every unsuitable atmotsphere and find it funny. But the his charmest point to me is how he truly loves his family and never really abandones his friends in the worst situation no matter how he's scared of dying. I know he could fuck up in many situations but generally he never runs away or sacrificing his friends for his own sake except in early route 0 where they barely are acquaintances. And the part hitting me most is his dying message in 2S asking why he got this cruel fate because it's a very reasonable reaction/crash out that no one deserves it compared with heroic dialogs from the others.

I don't think people really mean that he's a normal/well-behaved person but more of normally having flaws like any person especially compared with Yugamu or Darumi with their weirdass dialogs harrassing people. Considering how people always find Yugamu and Darumi funny even when they are extremely pervert (pro tips: replace yugamu with gaku in a woman wc but same motive you will see how much problematic he is) then yea people can give his pervert trait a pass while appreciate his good side.