
Questions like these are just weird to me. In return, you'd have to ask why people don't like Joowon. Or why they don't like Haesoo, or any other character. Whoever asks such a question expresses at the same time that it should be impossible and incomprehensible not to like this particular character, in your case Taku. Everyone has their own reasons, views, prejudices, feelings to like or dislike a character and often it's just very simple antipathy. There doesn't always have to be a reason. Maybe you're just looking for an answer, some proof, evidence, to what would be right or wrong. They are fictional characters. You can think and do what you want.
This is now my opinion, I like LoH and there are traits that I don't like about everyone. About Taku, in short, I can say, I did that many many moons ago, that I don't like his way of speaking. His choice of words. They carry a lot of burden.

Ikr what's not to like about a sociopath who first approached you because they wanted a quick fling during and used you for their own interest and later on got hella obsessed with you they thought it must be love, then they proceeded to pressure (read: emotionally manipulate) you into a (trial) relationship despite your unwillingness and when things didn't go smooth-sailing between you two (huh, wonder why that is?) they tried to once again pressure (read: more emotional manipulation) you into staying in the not-relationship by getting you a ring in a hope that they could tie you down and prevent you from leaving them because they're just that selfish. Omg guys like Taku are such boyfriend material
Wait people don't like Taku? lol wtf