What is your point? I don't believe you mean to imply that there's no relation between the former and the latter. In which case I assume you are just saying that it's whatever the publisher decided on (regardless of whether the work actually targets that demographic based om topics and general interest).so those tags don't necessarily indicate what kind of content the manga contains, just which demographic it was trying to target.
I mean Haru could have bought a phone to make it easier to communicate I don't know why you are blaming it on Mayu.