Apple is not even against other operating systems on Macs. Bootcamp has been a thing for a long time (and apparently they're not against ARM Bootcamp were it possible [1]) and recently marcan mentioned how Apple added something that wouldn't be helpful for Apple, but is helpful to the Asahi Linux project.
[1] https://www.macrumors.com/2020/11/20/craig-federighi-on-wind...
[2] https://twitter.com/marcan42/status/1471799568807636994