Hence why I couched the post in language like "business decision". Their company may have discovered a decades-old niche, in which they make money by having the image of a moral guardian, but we all know what the priorities of a business are.
Irrelevant of whether you think they live up to it, that is the reasoning of their decision. It's why my colleague takes her young daughters to see every Disney film, and why kids seem to have some fascination with dressing as Disney princesses.
But since you brought it up:
Say if someone involved in a Jewish history film had made a past joke on Twitter that the Holocaust was good fun, the SS were cool, and had been fired, would you question the past ethics of the company? Or would you see there might be a conflict of interest in allowing that person, no matter how nice, to remain on that film? Irrelevant of my feelings on the issue, Disney is a kid's company, who would have been employing someone who joked about raping kids. Hence why I said I sympathise, because there is no right answer here, a case can be made for either decision, because many people feel that doing nothing would be making light of a serious issue. But remember he has not been made a pariah like genuine criminals such as Weinstein. Life is complicated, and sometimes people who don't deserve to, can end up on the wrong side of poorly chosen words or choices, without any party being at fault.
I'm not sure what I would have done, probably kept Gunn if I had known him to be a good person. But I'm not a children's entertainer, so I can afford to be idealistic. Disney employs thousands and might not be so uninhibited. Maybe Disney isn't either an ogre, or a angel, but just a complex collection of conflicting people with conflicting motives?