There’s a distinction between one-to-one messaging and one-to-many messaging that needs to be considered. But in general, Google doesn’t control the email proto

There’s a distinction between one-to-one messaging and one-to-many messaging that needs to be considered. But in general, Google doesn’t control the email protocol so I don’t see a problem with them refusing to send an email they deem objectionable. This is why private email services and roll your own exist.