Because the ideology of promoting somebody like Trump is someone who is outside the system who alone knows how to fix it as it is entrenched and corrupt (like a vigilante to a cop). Oliver and company also constantly practice corporal punishment and see torture as an effective measure of interrogation. I don't agree with either of those things (especially that Trump is the answer to corruption for goodness sake) but looking at it from a conservative POV seems like it's up their alley no?

And sure the characters do often espouse socially progressive POVs (which is why I as a social progressive am at times able to look away from the more alarming elements) & the creators probably think they're being apolitical as the more conservative stuff is part of the tropes of the genre. I'd argue that actions speak louder than words myself but I still watch so their reasoning mustvwirk to some extent.

Anyway I'm not saying only conservatives can enjoy the show or find their ideology represented. Just saying if you're a conservative who doesn't watch because the creators are liberals and/or hate Trunp, watching the show might make you feel as if it reflects different values than the creator. Again, I'm a super liberal and obviously a super fan.