If you rock up and go, "we're doing this big thing tomorrow and oops sorry we didn't mention it before" of course you're going to encounter more push back.
On the other hand, if you get people on your team before doing something then they will trust you and possibly even become advocates!
This is politics! Politics is quite literally the development of consensus (whether it's corporate politics, national politics, etc.). Without consensus (agreement, buy-in), large-scale things do not get done. Politicking - which includes relationship building, framing, vision setting, leadership, debate and empathy, among many other things - is not necessarily intuitive. It is a skill like any other.
I think there's negative connotations about "politics" that people are implying within the context of corporate work environments. Specifically: arbitrary beurocracy, fragile personalities, back-channel communication, ego stroking, chest thumping and back-stabbing.
From a pure textbook definition of politics, yeah there's politics everywhere, and folk need to learn how to interact with coworkers in a healthy, productive manner. For folk going into engineering, I really like competitive student projects as a way to learn those skills.
If you rock up and go, "we're doing this big thing tomorrow and oops sorry we didn't mention it before" of course you're going to encounter more push back.
On the other hand, if you get people on your team before doing something then they will trust you and possibly even become advocates!