Lolipedos are similar to those True Crime fans who idolize school shooters and then go on to mimic the school shooters in real-life, actually shooting and killing people. Drawing fanart of school shooters or drawing porn of children is not normal behavior.
They like to compare pedophilic media to "violent videogames", but I think that's a bad faith apples-to-oranges comparison. A more similar comparison to lolicon is the True Crime fandom who genuinely act like murder is a cutesy/cool/edgy and good thing.
Going to elaborate further on my point, since "if you're against lolicon then you're against violent videogames" is a common flawed lolicon defense argument.
If you're ever seen a piece of media where there is a rape scene, usually the act of rape is not framed in a positive light for the viewer. Violent videogames usually do not portray murder, for the sake of pure bloodlust, in a positive light. Usually, there's a reason for the shooting you're doing in them. Things like first-person shooters are typically about opposing military factions, stopping terrorists, or being a superhero. Granted, there are some games like the Postal series, where you are genuinely playing as a psychopath on a killing spree. But Postal's protagonist is still clearly portrayed as a crazy mentally ill person. Not someone to look up to.
The thing with lolicon, is that it genuinely romanticizes child rape, and is typically written in a way where it portrays the child as "wanting it" or "enjoying it". You're also not fapping to violent videogames, but these people do fap to lolicon, so they're conditioning themselves to be turned on by children (See the concept of "Pavlovian conditioning"). When groomers tell their child victims, "You're so mature for your age", I think it's both 1) manipulation to get the child to feel like they're special, and 2) I think some of the pedophiles even trick themselves into believing that the children are more mature than they actually are. Pedophiles usually have deluded themselves into thinking what they're doing is "not that bad". This is why they always use the "teenager is close to an adult anyway" defense.
Psychological studies have been done which prove repeated fapping to things like this desensitize the viewer to it and lead to them having less empathy for actual real victims. Even just in their politics, you can tell fapping to 5-year-old anime girls has completely warped their worldview. They think little girls are "purer" than adult women, not as "tainted" by the modern world. So they justify wanting an underaged partner because they think adult women are "too tainted" and "couldn't possibly give them what they want". What you fap to doesn't exist in a vacuum.
Now, let's talk about the "True Crime Community (TCC) fandom", also known commonly as the "Columbine fandom", since the 1999 Columbine school shooting is one of the most popular cases they latch onto. This isn't the same as people watching true crime documentaries to understand criminal psychology. I am talking about the Tumblr/TikTok users who make fan edits of school shooters, draw fanart of them, cosplay as them, ship them, and even make porn of them.
Many of these people have gone on to try to reenact their own copycat mass shootings. There's a whole list of Columbine copycats.
They obsessively research these cases and like to read the journals/manifestos of the shooters. These fans are usually lonely and very mentally ill themselves, so they identify heavily with the shooters. They desensitize themselves so heavily to the idea of committing a mass shooting, and have grown so attached to the shooters they idolize, that they begin to see nothing wrong with the actions. Most are already suicidal to begin with, so their line of thinking is "If I'm going to already kill myself, why not get revenge too when I do it?". A lot of them view the shooters as the "true victims" because of their mental illness. Similar to how a lot of pedophiles will feel like they're an "oppressed minority" for having a "taboo sexuality".
They overempathize with the perpetrators (school shooters or pedophiles) and do not empathize at all with the victims (the killed people or the children raped). A lot of Columbine fans wish they could have befriended Eric and Dylan IRL, and a lot of lolicons wish they could have sex with their underage waifu IRL.
It's for this reason that YES, what you consume, and especially fap to, does affect your brain.
If fiction truly does exist in a vacuum, then propaganda wouldn't be an effective political tool. Propaganda often uses fiction. Lolicon antisemites are a joke because they fail to realize that pornography pushes themes like race-mixing, transgenderism, and pedophilia to be normalized and more common. And it's not "just Western pornography" because trannies exist as futas in hentai and lolicon is pedophilia. If they can call out liberal women for being brainwashed into accepting immigration, then I don't know why it's so hard for them to realize they themselves have also been brainwashed into inceldom by Internet ragebait. A lot of them genuinely do think women are all potentially secret OnlyFans whores.