IMO, a lot of people who didn't like the decision (whether because of which justices decided it or for some other reason) latched onto the "SCOTUS decided that corporations are people" shorthand because it seems absurd taken literally. Corporations are clearly not people (natural persons) the way you and I are.

But saying that corporate personhood shouldn't include political donations as part of their free speech rights, while a perfectly reasonable position and I might even agree, doesn't make as good a soundbite.