Monosodium glutamate is there as a flavoring, just like any number of seasonings. Nobody says that thyme or oregano shouldn't be in food unless they help preserve it longer. There's no evidence whatsoever that it's harmful to anyone, and it's a common part of Asian cooking. The furor over MSG is that it has kind of a funny name and people are still in a tizzy about the racist panic over "Chinese restaurant syndrome" from a few decades ago.[1]

1) https://www.theguardian.com/lifeandstyle/2018/may/21/chinese...