It is, as pornography is about sexual acts, while the manosphere is discussing the role they believe men and women should play in all aspects of life, not just sex and romance. They believe and teach that women shouldn't be managers, knowledge workers, professors, politicians, shouldn't have a right to vote (at least not differently from the man who essentially owns them) etc.

Pornography may give some people some wrong ideas about sex and romantic relationships, might even instill some level of implicit misoginy in certain straight men, but I'm pretty sure you won't get the idea that women should be allowed in Parliament from watching too much porn.