You're misrepresenting things a bit there. I didn't just go "not a good reason!" - I explained WHY it's not a good reason. You also used a subjective criterion in this analogy - "stink" doesn't just denote the existence of a smell, it makes a value judgement (i.e. bad smell). You've smuggled in a subjective position that's guarded against objective reasoning, but that's NOT what happened in the original example - as evidenced by me giving you objective reasons why the internal logic of your statement was problematic.
That's more like you going "I hate cats" me going "okay why?" and you going "because they have five legs". I then point out that this is demonstrably false, but you go "well let's just agree to disagree, I hate cats and you don't, the end". You simply avoided having to talk about the problem with your REASON and tried to go back to the CLAIM, invoking subjective preference so as to not explain the objection to your justification.
And let's be clear: in that example, you are totally fine to keep hating cats, just like you are fine believing that "it's not like the book" is a good reason to exclude people based on skin color. That's your preference. It won't CONVINCE anyone, though, and people can look at it and go "that's a pretty racist position to have", but that doesn't mean you can't have that position. If you want to JUSTIFY that position, you need to engage with the arguments, and that means responding to objections. If you don't want to justify it, you can just move on and let people think what they think.
You can't have your cake and eat it, too - you can't have a preference you don't need to defend and ALSO expect it to convince people to respect your position. They respect that you HAVE a position, that doesn't mean they have to respect the position ITSELF.