Not just all people but all beings whatsoever deserve our respect. Many additional specialized considerations apply to beings subject to ethical appraisal (“us”), and a lot of the time I focus on these. Mutual recognition in the strong sense applies only between ethical beings, and thus only between potentially rational or talking animals, but the ethical significance of mutuality is much broader than that.
I want to say that a good ethical being claims no unequivocal mastery over any other being, period. Every being — even including inanimate objects — is to some extent an end in itself, and not simply a means to our ends. Of course, we are not unequivocally subordinate to the ends of any being, either, so it it not always wrong to sacrifice other beings to our ends. (We must eat, for instance.) But as ethical beings, we ought to be careful and thoughtful about how we achieve our ends. We are stewards, not masters.
There can be no simple rule about whether the end justifies the means. Sometimes it does, and sometimes it doesn’t. The answers are in the details of each case. Full evaluation of such questions could only be achieved by the universal community of all ethical beings, but the universal ethical community and its principles are not a finished achievement, only a work in progress. Nonetheless, ethical beings implicitly deliberate on behalf of all beings, not just on behalf of themselves. (See also Natural Ends.)