It is not generally accepted. Sometimes it is morally accepted but not generally accepted unless if you give credit (which many don't do).
Charities do not do this at all as getting sued is disastrous for a charity and will legitimately just straight up kill the charity.
The other problem I see is the fact that companys automate the systems to automatically send copyright notices.
My point in this is that I am not annoyed for people not commissioning art (but if you have money you should do it). I am annoyed at people not crediting and not asking the artist. I am annoyed at a general lack of knowledge of copyright which over these years people just know as a "YouTube thing that hurts creators".
It IS generally accepted. Using copyrighted images for non-commercial stories on the net has been an accepted practice for decades, ever since stories were shared through newsletters in the 90s. It's normal in many different writing platforms that do not monetise their stories. It's normal. Ai-chan disagrees with making it a big deal now that we already accepted that it's normal.
Why was it tolerated by the artists? Two reasons.
One, because this is a victimless misdemeanor. The readers and artists understand that the art used is merely a representation of the story and not assumed to be taken as an intellectual property theft. In some cases, stories have been written based on the copyrighted images themselves. Nobody complained for the longest time.
Two, because if the artist wants to take actions, they can. DMCA allows them to copyright strike the item in question. But before that, they would have to prove that they own the copyrighted materials. Alternatively, they can simply ask the author in question to just take them down, and this has been done for decades. It's all for fun, you just tell the authors, "I don't approve, can you take my art down?" and the authors would agree. It's not a big deal.
As for charities using copyrighted materials, Ai-chan can't give evidence now as it was discovered over the course of many years. Don't know what happened to them, nor the names of the organisations. However, there was a political campaign by a Malaysian politician that used a recoloured drawing of Alice Margatroid in 2014. Everyone knew it was Alice Margatroid, but everyone was fine with it because it was not meant to be an intellectual property theft. The politician was simply trying to appeal to the younger audience. It didn't really work though, as Malaysians mostly saw it as cringy.
