First of all, should businesses involved in weddings, such as cakemakers, florists and wedding photographers, be required, if asked, to participate in same-sex weddings.
At the time of the six o'clock swill, businesses could still technically refuse to serve anyone for any reason or none. Later we introduced various anti-discrimination laws, and so businesses were no longer allowed to refuse to serve if this violates these discrimination laws.
The requirement for a private business to serve people under some circumstances and in particular, serving some (such as women and minorities) was a condition for serving white men, was a new thing. Before, they were never required to serve anyone.
Apparently, private clubs are exempt from discrimination laws, and I believe there are compelling reasons why they are. This means that most supermarkets may not discriminate, but wonder Costco is technically permitted to do so, because only members may shop there. However, each member is allowed to each take a limited number of non-members there, so I'm not sure if it still counts as a private club.
But Costco is the only warehouse club operating in Australia and has an economic incentive for allowing people to join regardless of fundemental traits like race, gender and sexual orientation. They can have more members and thus get more money from goods sales and membership fees.
But anyway, maybe we should debate about whether refusing to serve wedding cakes, wedding photography, etc, to same-sex couples should be banned upon redefinition of marriage in Australian law. See this news article, and also this piece.
Less than 10% of the general population are in commited same-sex relationships and there is an abundance of cake makers and florists (I don't know about wedding photographers), the vast majority have no objections to same-sex weddings. Ones that have, say, religious objections to same sex marriage are exceptions.
Is there anyone who, given the statistics I gave, simply avoid buying any cakes or flowers from businesses that have such objections, whatever anti-discrimiation laws may say?