Reddit mentions of The Culture Series of Iain M. Banks: A Critical Introduction

The Culture is the "enemy" in Consider Phlebas; Banks is setting things up for the rest of the series by seeing things from Bora Horza Gobochul's viewpoint in this book. So no, the other books aren't as full of torture and gore as CP. Violence there definitely is, even though it is more of the "impersonal millions dying" type.

You also have to remember that Banks dreamed up/wrote The Culture books at a time when space opera had been in a coma for many, many years. He re-defined what space opera (and SF in general) could do/should be; something similar to what GRRM did many years later for fantasy. If you've read modern space opera/SF before reading The Culture, it might help keeping this in mind.

I'd also recommend reading Banks' A Few Notes on the Culture, which he wrote much before the novels. If you want a more critical look at The Culture, Simone Caroti's book is really good.

I haven't read this myself, but it might help:

The Culture Series of Iain M. Banks: A Critical Introduction by Simone Caroti

https://www.amazon.ca/Culture-Iain-M-Banks-Introduction-ebook/dp/B00WAKN7XK

https://www.amazon.com/dp/B00WAKN7XK/ref=cm_sw_r_cp_dp_T2_w9FBzb43ZZX35