>> We have trended from subjective language to objective language. Why?

Alternative theory: asynchronous communication.

It used to be your speech stayed with you, and if you were unprecise, or misspoke, or was caught meandering off-topic, people could just ask you and you would clarify. With exception for authors and journalists, that were explicitly taught how to write.

Now, your speech stays while you leave, so you have to construct as precise of an image as you can. If you misspoke or said something wrong, people have to engage with your speech as-is.

People can ask you to clarify online, of course. But you have to build a solid foundation, before people even start to think that they could benefit from a few clarifications.