I dunno, I do all my work from the ground up; taking my own screencaps (or searching and crediting others for the specific ones I want), cropping, filtering, making things legible/not too sharp/not too blurry/lightening/darkening/etc etc. I like my work to look a certain way, and it takes some effort for me to be entirely happy with them. Other people might be fine cropping an image, slapping colors on it and calling it a day, and that's fair enough, but I work at what I do. Maybe I'm the one doing it wrong? But just because an icon looks "simple" and clean, doesn't mean there wasn't a lot of work involved to get it there. So, yeah, I don't think it's that hard to save the username as the filename for an icon.

I will also add that on the icons I do just "slap together," I will put up a note that says the bases are free to grab and alter, but for the most part that's a rare occurrence.