Because the archive is a useful, easy and accessible place to include them, and no one else seems to care about preserving these visual fixes (and I don't think the ones in the archive have been integrated into the emulator yet). That's why I made the archive in the first place since no one else seemed to care about organizing the patches in an up-to-date fashion.
I've had this on the archive notes for the longest time so it's not like I kept it a secret from anyone:
"Many of the patches in this archive also contain other useful features, making this archive a must for all PS2 gamers. For example, the Fatal Frame patches contain codes which disable extremely blurry cutscenes (due to poor upscaling). Other codes also fix visual glitches, and also contain "noise/grain filter" removal codes."
It's a free graphics boost which no one has complained about (except the noise effects being disabled by default which only like one or two people complained about, but let it slide since I prefer them disabled). You're the first one I've seen who has complained about their inclusion here.
If we kept it to widescreen hacks only, then we'd have to make a third archive, although I could make a GSDx hacks folder in the "useful cheats" section of the archive if it bothers you that much.
Keep in mind, I think there's only about 10-15 games which have gsdx fixes, and I'm not the one who made all of them. Some people have included them in their patches and I archived them. Unfortunately, I haven't kept track of them as I go, so it would take me so much time to find them all, but I could put the few I know in there. I also know there's a code to prevent the weird lines in KH's HUD:
https://www.youtube.com/watch?v=fFssbQ_ppP8
On another note, I'm probably going to enable the "optional zoom for cutscenes" for KH2 by default since I've noticed too much pop-in on the left and right during cutscenes, and it breaks immersion.
I'm also going to another archive update on the first day of the new year, since it's been like 4 months since I've last updated the archive.