After boarding the carriage, Kanzaki Kumo began writing a letter to Kagaya explaining Inosuke's general situation and asking him to find a Cultivator with a good enough temper to teach him a Breathing Style.
Inosuke still lacked much of the common knowledge of human society, and he had yet to shed the "wildness" he had acquired growing up in the mountains. His words and actions often unwittingly provoked others.
Besides, growing up rough in the wilderness had given him a set of the most primal fighting skills, even without systematic martial training. An ordinary person might not be able to make him behave.
He was relatively well-behaved around Kanzaki Kumo because Kanzaki Kumo had previously appeared behind him without a sound and could see through his trick of shifting his internal organs. That had made him understand that he could not beat Kanzaki Kumo.
This most basic reasoning actually worked best on Inosuke.
But aside from the few who had retired from being Hashira-level Swordsmen, the Demon Slayer Corps' Cultivators might not actually have the strength to subdue Inosuke.
According to Kanzaki Kumo's memories, Wind Breathing suited Inosuke relatively well. In the original story, his Beast Breathing was considered an offshoot of Wind Breathing, which he had created himself after fighting a Wind Breathing Swordsman and unleashing the power of "seems right to me."
Although starting with another Breathing Style would not necessarily prevent Inosuke from creating his own, it was better to play it safe with something like this.
The current Wind Breathing Cultivators in the Demon Slayer Corps were only average in strength. They were good enough to guide a beginner, but getting Inosuke to obey would probably be a struggle.
If strength could not subdue him, there was only one other way to make Inosuke listen-enough patience