I do not care about Kimmel or Kelly at all and do not know the details of their cases, so my post is not about them specifically. I do think it's ridiculous how people excuse their own party's trangressions a lot more easily. However, I think sometimes your comparisons get stretched too much.
If somebody apologizes for something that they did once and do not continue a pattern of bad behavior, that is a lot different from someone who does something very offensive, won't apologize it and continues to do offnsive things throughout their lives.
An example of the former would Be Obama's "special olympics" comment. It was really disappointing and inexcusable when he said that. He then apologized and never said anything remotely like that again. It is still a bad mark on him because no President should say anything like that, but it's something that can now be mostly excused. Then you have Trump who says or does offensive stuff like that pretty much every day of his life, never apologizes and usually never admits to it and continues to show that his bad behavior is exactly who is. Yet, his followers still look up to him like a god. Just to give an example on the left, I present Bill Clinton, who (although not quite in Trump's class) was and still is an unapologetic pig.