The SEC cares about the public in general. Tesla shareholders are part of the public. So are potential investors who do not currently hold stock, and investors

The SEC cares about the public in general. Tesla shareholders are part of the public. So are potential investors who do not currently hold stock, and investors who short Tesla and/or invest in its competitors. There is absolutely nothing wrong with trying to minimize harm to Tesla shareholders, in fact that would be part of the SEC's stated mission. However, it is not the only part. If Musk used fraud to inflate Tesla's share value, benefiting Tesla shareholders but harming many other people, then the SEC would still intervene. In other words, it's a consideration, but not the only one.