Can't read the Chinese (Japanese? Korean? Russian?) but I'm pretty sure Rammus is overconfident with his 500 Magic resist until Caitlyn points out the entire enemy team is AD (Who's counter would be Armor)
Magic resist is still magic resistWhy are you building magic resist items?I spent a lot of gold for all these items that increases my magic resistance!Because they give me high defence against magic!But everyone in the enemy team is AD....your magic resist is not helping!