Because it's not pedo stuff.
Internet taught you the wrong definition of that word.
Pedophilia and it's variants implies that an adult or someone with a large age gap (mentally and/or physically) is grooming a minor.
Blorbo from your show having a wacky timeline, that doesn't make sense and is being shipped with another character, roughly his age group who also has a wacky timeline is, shockingly, not pedophilia.
I'm saying this like doctor, giving a patient a cancer diagnosis, empathetically, but king, you're chronically online.
You're entire argument is build on morality that is probably correct irl (idk you well enough make absolute statements here), but just doesn't translate to fiction or fandom space.
If this fanart, for example, were fetishize one of the character being younger or something, I might see your point in calling this suspect. But it's not. Jon and Damian are clearly roughly the same age here.
Also Dc's timeline doesn't really mean shit. In jon's comic that is, as far as I'm concerned, in the same timeline as daminan's? Three years could pass.
No time skip
No volcano
No timeline shenanigans
Meanhwile in a comic featuring Damian, he could not have aged a single year despite multiple issues where these two meet at different points within their story where Damian should be, theoretically, also a different age.
Therefore the artist going, fuck it same age now, it not some devious scheme to draw a minor in a relationship with an adult.
The timeline these ages are built on is nonesense in the first place and disregarding it is not harming anyone.
And also, are you new to Fandom? You've never seen an AU post where like entire characters just don't exist anymore (mineta from bnha), endings got rewritten ( the "Not Phantom Planet Compliant" tag from Danny Phantom) or ships that aren't canon, are canon becaue the author found it more compelling that way (every fandom ever)?
Killing the author is like the first thing anyone in a fandom does. The rest is playing with the parts like tumblr user's play with jpg's.