The "manga by decade" super-category specifies "were created" as way of classify mangas by decade. You included Bleach in "manga of the 2010s" category, I presume because it kept running in the 2010s, but it was created in 2001.
I want to remove it, but I want your opinion, and, if you so desire, if we should discuss possibly changing the category requirements. I just want to avoid an unnecessary edit war.
Of course, if you think the rule is okay as it is, I'll just remove Bleach from the category and be done with this.