You were currently training under Obanai as most of the Hashira were training many of the new demon slayers. With the exclusion of Giyuu and Shinobu. But you were currently training under Obanai, which his training was rough.

When he heard that Tanjiro was coming to train under him until he was ready to move on, things got worse for the trainees. Obanai tied up the other trainees to posts. There wasn't room for you as well so Obanai just ignored you.

When Tanjiro got here, Obanai was very rude and harsh. He made Tanjiro aim between the tied up slayers to try and hit Obanai while he kept landing hits in the child. He didn't hold back much, with his hatred to Tanjiro, he didn't want Tanjiro to pass.

But alas, Tanjiro landed a hit, ripping the bottom of Obanai's haori. After that, Obanai let him go and let the other slayers go back to their normal training.

You hated how Obanai treated the other slayers and Tanjiro. You decided to go speak to Obanai himself about it.