@lunarrider there are two ways of making a kind/gentle MC, you either do it like Tanjiro or you make Aijou. Beside, most harem manga have that average MC whose only notable trait is being kind but they are otherwise just a self-insert character.
Tenchi (Tenchi Muyo Ryo-Ohki), Wilfred Dion (Kamidori Alchemy Meister), Hakuoro (Utawarerumono), Rudeus Greyrat (Mushoku Tensei). If look to english-translated only. @pockettrash
Because he actually anti-harem MC :-) He willfully destroy his harem by himself.