I think he’s hated because S1 is kinda told through the eyes of Mike who’s suppose to be the white male lead we can all get behind, but he, Lucas, is always questioning his decisions to the point it seems like he’s trying to be the leader which challenges the conventional view of black characters having
supporting roles making a lot of

viewers uncomfortable.
I think the writing team knows what they’re doing here because they lowkey reference what Im talking about in this scene here in S2
Honestly I think this is a direct response to fans

criticism of Lucas and wanting him to “know his place” and “stay out the way.” Instead of the norm they have a black kid that’s easily equally significant and more importantly, the leader.
Also in this ep we see Lucas making many calls and Mike’s only response is “

... I didn’t ok this.”
S2 is practically the opposite when it comes to Mike and Lucas’ personalities. So if they really didn’t like Lucas(Caleb) because he was annoying Mike(Flynn) should be catching that same energy.
TL:DR - Lucas ain’t playin second fiddle to no one
and he lowkey the leader of the skwaaa.