Reactions count as likes?

Not in my experience. When people use :angry: or :astonished:, they could be responding to the author of the post. But more commonly, they are responding to the content of the post.

For instance, if I write that my neighbor didn’t clean up their dog’s :poop: in my front yard, it doesn’t make a lot of sense to use :+1: or :heart: in response. Nobody likes :poop: where it doesn’t belong! So I’d expect :angry: or :astonished: reactions to be directed at the neighbor in the post, not at the post itself. :face_vomiting: or :poop: would be even better, of course. Not sure how common those emojis are as reactions, though.