@Litrojia
Even with filters, galleries represent the potential to have unusually high concentrations of themes, fetishes, or graphic content that you normally would not see in a typical search of the site.
And not everyone has filtered everything they might not want to see, because they’ve never seen “that much of it” in one place. Perhaps just browsing the site with the everything filter works fine for them because it’s not an entire page of the one thing they get triggered by.
But with galleries, it’s not just “the random images in this one tag”, it’s a curated gallery of images that someone has hand selected, sometimes highlighting what they consider “the best of the crop” in whatever theme they are focusing on.
The potential for someone accidentally wandering in to a gallery exclusively dedicated to some a subject they might never have otherwise filtered is high.
So even though filters exist, it is a courtesy to others to let them know what they are going to see when they open that gallery up.
Using my own galleries as an example, I am pretty sure people browsing a fun site like this will generally not be prepared for what they’ll see if they open my gallery “Best Pony”.
Sure, it’s pages of happy fun fine to see at work. Then it’s an entire page of ”Best Cockmare”. Even if people are using their filters, gallery is built from an extremely particular view of “Best”. And I wouldn’t be a bit surprised if it were triggering for some users even if they think they are “filtered up”.