We haven't reached that part of the lore yet. It's likely that we'll get answers in future updates, so we'll need to be patient and wait for more information.
Maybe because he is different from other humans. He doesn't hate the judge even though he assisted on his killings. And An Zhe his gaze when he is looking at him is full of compassion. While everyone is afraid of him, he isn't. There are many reasons ╮(￣▽￣)╭
iirc lu feng really had a high judgment rate like ~96% so it really intrigued him that an zhe wasn't a xenogenic and then they happen to meet everytime with an zhe's instances so lu feng during these times was kind of "curious" about him ... and lu feng still doesn't know that an zhe is a mushroom that he took a spore from so it was really just curiosity or anything in line with that (=・ω・=) their story will continue to progress later on
can someone explain why the judge gives mushroom special treatment? it's obvious the judge has his spore, but what's the explanation behind him liking mushroom from the very start?