Exactly. "shareholder activism" is called that because it is a considered an anomalous, bizarre state of affairs. Imagine the temerity of the people who own the shares of the company calling the shots! In reality, management has basically a completely free hand to do whatever they want so long as an incumbent board doesn't get its shit together and replace them (and even that is sometimes not enough).

This is also beside the main point, which is that management shares a class interest with shareholders, even if they aren't literally the same people at some particular point in time. Capital and management are obviously on the same side, and labor isn't part of the club.