"Check yourself before you wreck yourself"
Very doubtful this is the original line.
"Everything is political"
This is the phrase only pure nuisances spout. Suddenly everything is open to irrelevant sociopolitical critique. It's often spouted by journalists and bloggers to put neck-breaking spins on things they cover, often to the economical detriment of their target. What is simply a problem for a protagonist to resolve or minor detail is now some kind of explicit statement. The issue being these may not be statements by the authors at all, but just interpreted as such.
While I don't disagree that "black companies" touch on politics, to a normal person it may just means "an abusive company; the antagonist" and might sympathize if they've ever had a shitty job. The manga is not "heavily" political as you state. It isn't the focus at all. There is are no explicit political statement. You can interpret everything from a political view if you're an obsessed nut, but what you consider "politics" may simply be considered a normal issue.
I see the black magic industry reform merely as market forces which IS explicitly stated by the boss in early chapters as lowered revenue, poor PR, and lack of skilled workers.
"Hate speech"
A meaningless phrase.
We live in the era where the OK hand symbol is a hate sign and where simple observations imply hatred.
Also a phrase used by shitty propagandists.