Disclaimer: I don't believe media, playing games, etc., makes people do bad things. Also, long post, feel free to skip.
That said, media can have some influences. Those with proclivities towards acts of sadism can be attracted to certain themes in media. Similar to how a priest doesn't make one a child molester, it just so happens that it's an attractive position because it brings them closer to potential victims.
IMO there's also a difference between watching regular violence and media with a sexual basis. Media that prompts a strong physical response, like orgasms, can work like (psych 101) pavlovs dog: Dog salvates in presence of food. Person rings bell. Eventually bell prompts response without food present. Human is aroused by imagery, masterbates until orgasm. This is repeated. Now there's an association between that type of imagery, arousal, and getting off.
Fetishes are made all the time. Another example: Chinese foot binding. Started as a foolish fashion trend from a story, continued because it became a widespread fetish. So much so, that it became a necessity for finding a husband. There was nothing about it that could've been argued as being naturally embedded into human sexuality. Rotten, distorted flesh by natural instinct, would in fact be a turn off. Point being; The men weren't "born that way".
There's good influences too. Theories on human empathy increasing (to where we can see brain structure changes from past humans, from growth in that part of the brain), attribute some of it to literature. When literacy became widespread, empathy for others did too. You can see direct correlations between the overnight rise in human rights activism and popular literature depicting sympathetic, relatable characters being read by the greater public. Shawshank redemption was responsible for raised awareness about treatment of prisoners by humanizing them. So media can influence by being inspiring, as an emotional outlet, and put a mirror on our values.
So no, I don't support the idea that lolicon is good for preventing sexual abuse. If anything, it can be attractive to those that already have proclivities towards seeing children as sexual, and worse, if they're getting off to that, training themselves to find the characteristics arousing. While making it illegal is a too complex, society should find ways to shout distasteful depictions down, platforms should be mindful of content, and in no way should people become complacent about the sexualization of children, no matter the form it's presented in.