The precedent has already been set by laws preventing the refusal of services based on gender or race or ethnicity. One of which comes from the Civil Rights Act, passed fifty fucking years ago.
Do you really expect anyone to be swayed by “I don’t agree with the opinions these people have, so I should be allowed to refuse their business.”? Because the KKK members shown here are not engaging in any acts besides wearing costumes associated with bigotry. They’re expressing an opinion, and no, businesses should not be allowed to turn people away just because of a difference of opinion.
And how is buying a cake (which requires them handing the guy money) sticking it to him?
This varies by jurisdiction, but sexual orientation is *not* currently a protected class at the federal level. Therefore the Civil Rights Act does not come into play. Currently, a business owner would be free to refuse service on the basis of sexual orientation unless there was a state or local level statute that named sexual orientation as a protected class. (In Arizona, I *think* there is such a statute in Phoenix for public accommodations, but I couldn’t find anywhere else in AZ where this was true.)
This spate of laws going around these days merely *anticipate* the future climate where there is blanket federal or perhaps widespread state adoption of sexual orientation as a protected class, which seems likely given where we are (finally) moving with regard to marriage equality. So in the future where sexual orientation is a protected class, people of a certain religious bent want an exception to the rules for their special snowflake selves. We do already have such exceptions carved out, but in general they only go to not-for-profits with primarily religious missions, eg the Salvation Army not having to hire non-Christians, etc.
To get back to the Klan Kouple and the Black bakery owner pictured in the cartoon this exchange is about, the Black bakery owner does not have to serve the Klan Kouple, as being a racist is not a protected class. (Though to be clear, he couldn’t say something like, “I won’t bake this cake for you because
you’re over 40” because age over 40 is also a federally protected class.* you’re not from the United States” because national origin is a protected class.) And also, it’s even further removed from being a good analogy because it doesn’t seem TOO likely that the Black bakery owner would cite religious reasons for not wishing to to business with the Klan Kouple. I won’t even get into the part where in this scenario Klan Kouple is supposed to be analogous to an oppressed minority.
*oops, looking it up again, I think age over 40 is only a protected class for employment, not for public accommodation.