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I watched it a few times.

You are trying to claim that because he is labeled a comedian, anything bad he says can be absolved because he was making a joke.
But he made no joke. His statement cannot be construed as a joke.

Now, ABC is the holder of the right to free speech in this case, not Kimmel. They are also the holder of the FCC license and obligation to follow the laws set forth when using public airwaves for their broadcasts.
They could have chosen to keep Kimmel on the air and continue to artificially support the financial money pit that his show was. If the FCC ever did anything about Kimmel's violation of the law, they could have taken the case to court.
But ABC and Disney decided Kimmel was wrong and that his words were false, offensive, and inappropriate.
They did ask Kimmel to apologize, he said no. They asked Kimmel to back off and drop it. He said no and planned to go all out in his next serious monologue the next night.
So Kimmel's employer canned his show because they knew they couldn't defend this loose canon's actions based on FCC rules, and they decided that he was more trouble than he was worth.

They saved themselves a LOT of money, made inroads with the audience base that will help them recover their rating, and most importantly did the right thing.